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Coskun A. Prediction interval: A powerful statistical tool for monitoring patients and analytical systems. Biochem Med (Zagreb) 2024; 34:020101. [PMID: 38665871 PMCID: PMC11042565 DOI: 10.11613/bm.2024.020101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 01/23/2024] [Indexed: 04/28/2024] Open
Abstract
Monitoring is indispensable for assessing disease prognosis and evaluating the effectiveness of treatment strategies, both of which rely on serial measurements of patients' data. It also plays a critical role in maintaining the stability of analytical systems, which is achieved through serial measurements of quality control samples. Accurate monitoring can be achieved through data collection, following a strict preanalytical and analytical protocol, and the application of a suitable statistical method. In a stable process, future observations can be predicted based on historical data collected during periods when the process was deemed reliable. This can be evaluated using the statistical prediction interval. Statistically, prediction interval gives an "interval" based on historical data where future measurement results can be located with a specified probability such as 95%. Prediction interval consists of two primary components: (i) the set point and (ii) the total variation around the set point which determines the upper and lower limits of the interval. Both can be calculated using the repeated measurement results obtained from the process during its steady-state. In this paper, (i) the theoretical bases of prediction intervals were outlined, and (ii) its practical application was explained through examples, aiming to facilitate the implementation of prediction intervals in laboratory medicine routine practice, as a robust tool for monitoring patients' data and analytical systems.
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Affiliation(s)
- Abdurrahman Coskun
- Department of Medical Biochemistry, Acıbadem Mehmet Ali Aydinlar University, School of Medicine, Istanbul, Turkey
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2
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Plebani M. Harmonizing the post-analytical phase: focus on the laboratory report. Clin Chem Lab Med 2024; 62:1053-1062. [PMID: 38176022 DOI: 10.1515/cclm-2023-1402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 12/27/2023] [Indexed: 01/06/2024]
Abstract
The final, post-analytical, phase of laboratory testing is increasingly recognized as a fundamental step in maximizing quality and effectiveness of laboratory information. There is a need to close the loop of the total testing cycle by improving upon the laboratory report, and its notification to users. The harmonization of the post-analytical phase is somewhat complicated, mainly because it calls for communication that involves parties speaking different languages, including laboratorians, physicians, information technology specialists, and patients. Recently, increasing interest has been expressed in integrated diagnostics, defined as convergence of imaging, pathology, and laboratory tests with advanced information technology (IT). In particular, a common laboratory, radiology and pathology diagnostic reporting system that integrates text, sentinel images and molecular diagnostic data to an integrated, coherent interpretation enhances management decisions and improves quality of care.
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Affiliation(s)
- Mario Plebani
- Clinical Biochemistry and Clinical Molecular Biology, University of Padova, Padova, Italy
- Department of Pathology, University of Texas, Medical Branch, Galveston, TX, USA
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3
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Dülgeroğlu Y, Ercan M. Biological variation of serum neopterin concentrations in apparently healthy individuals. Clin Chem Lab Med 2024; 62:706-712. [PMID: 37882748 DOI: 10.1515/cclm-2023-1030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 10/17/2023] [Indexed: 10/27/2023]
Abstract
OBJECTIVES The aims of this study were to determine the biological variation (BV), reference change value (RCV), index of individuality (II), and quality specifications for serum neopterin concentrations; a measurand provided by clinical laboratories as an indicator of cellular immunity. METHODS The study delivered serum samples collected for 10 consecutive weeks from 12 apparently healthy individuals (3 male, 9 female). Serum neopterin concentrations were measured using high-performance liquid chromatography with fluorometric detection. The data analysis was performed using an online statistical tool and addressed published criteria for estimation of biological variation. RESULTS The mean neopterin concentration was 5.26 nmol/L. The within-subject biological variation (CVI) with 95 % confidence interval (CI) of neopterin serum concentrations was 11.54 % (9.98-13.59), and the between-subject biological variation (CVG) with 95 % CI was 43.27 % (30.52-73.67). The neopterin asymmetrical RCV was -24.9 %/+33.1 %, and the II was 0.27. The desirable quality specifications for neopterin were <5.77 % for precision, <11.20 % for bias, and <20.72 % for total allowable error (TEa). When analytical variation was used instead of CVI to calculate TEa, the desirable TEa was <18.39. CONCLUSIONS This study determined BV data for neopterin, an indicator of cell-mediated immune response. Asymmetric RCV values, of 24.9 % decrease or a 33.1 % increase between consecutive measurements indicate significant change. The II of 0.27 indicates a high degree of individuality, therefore that it is appropriate to consider the use of personal reference data and significance of change rather than the reference interval as points of reference for the evaluation of neopterin serum concentrations.
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Affiliation(s)
- Yakup Dülgeroğlu
- Department of Medical Biochemistry, Yenisehir State Hospital, Bursa, Turkiye
| | - Müjgan Ercan
- Department of Medical Biochemistry, Afyonkarahisar Health Sciences University, Afyonkarahisar, Turkiye
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4
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Odabasi MS, Yalcinkaya Kara ZM. Are tube fill volumes below 90% a rejection criterion for all coagulation tests? Lab Med 2023:lmad108. [PMID: 38104249 DOI: 10.1093/labmed/lmad108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023] Open
Abstract
BACKGROUND Rejected samples lead to prolonged turnaround time and delayed diagnosis and treatment of patients. This study was conducted to determine minimum acceptable sample volume in Sarstedt brand coagulation tubes to reduce high sample rejection rate. METHODS Blood samples were drawn from 20 participants (10 healthy volunteers and 10 patients receiving oral anticoagulant) into coagulation tubes. Six samples were taken from each participant, with tube fill volumes of 100%, 90%, 80%, 70%, 60%, and 50%. Prothrombin time (PT), active partial thromboplastin time (aPTT), and fibrinogen tests were analyzed. RESULTS According to quality performance specifications, the tube fill volume must be at least 70% for PT and aPTT and 50% for fibrinogen. There was no statistical difference in samples from healthy volunteers for PT, aPTT, and fibrinogen tests when the minimum tube fill volume was at least 80%, 90%, and 50%, respectively. These percentages were 50%, 70%, and 60%, respectively, in patients receiving oral anticoagulant. CONCLUSIONS Sarstedt tubes meet quality standard specifications at a 70% fill rate for PT and aPTT and a 50% fill rate for fibrinogen. Comprehensive studies with larger populations are needed to accept these values as sample acceptance criteria for the laboratory.
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Affiliation(s)
- Merve Sena Odabasi
- Department of Biochemistry, Sisli Hamidiye Etfal Research and Training Hospital, Istanbul, Turkey
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5
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Mortier F, Daminet S, Duchateau L, Biscop A, Paepe D. Biological variation of urinary protein: Creatinine ratio and urine specific gravity in cats. J Vet Intern Med 2023; 37:2261-2268. [PMID: 37828720 PMCID: PMC10658522 DOI: 10.1111/jvim.16881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 09/13/2023] [Indexed: 10/14/2023] Open
Abstract
BACKGROUND Laboratory results are influenced by presence and severity of disease, as well as preanalytical factors, analytical variation, and biological variation. Biological variation data for urinary protein: creatinine ratio (UPC) and urine specific gravity (USG) in cats are lacking. OBJECTIVES Determine the biological variation of UPC and USG in cats. ANIMALS Eighty healthy client-owned cats. METHODS Prospective study. Urine was collected on days 0, 14, and 56 from all 80 cats to investigate the persistence of borderline or overt proteinuria or suboptimal urine concentration. In 15 of these cats, urine was collected weekly from day 0 to 42 to calculate the index of individuality (II) and reference change value (RCV), and on days 56 and 57 to evaluate day-to-day variability of UPC and USG. RESULTS Borderline or overt proteinuria (UPC ≥0.2) was present in 18/80 (23%) cats at baseline and persisted on 3 occasions in 2 months in 8/18 (44%) cats. Urine concentration was suboptimal at inclusion (USG <1.035) in 8/80 (10%) cats and at all 3 time points during 2 months in 3/8 (38%) cats. The II of UPC and USG indicated intermediate individuality. The 1-sided RCV was 82% for UPC and 36% for USG. Proteinuria substage was identical on 2 consecutive days in 13/15 (87%) cats, and urine concentrating ability remained the same in all 15 cats. CONCLUSIONS AND CLINICAL IMPORTANCE A >82% increase in UPC in a healthy cat is not solely attributable to physiological and analytical variation. For USG, a decrease of >36% is considered clinically relevant.
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Affiliation(s)
- Femke Mortier
- Small Animal DepartmentGhent UniversityMerelbekeBelgium
| | | | - Luc Duchateau
- Biometrics Research CenterGhent UniversityMerelbekeBelgium
| | - Ann Biscop
- Small Animal DepartmentGhent UniversityMerelbekeBelgium
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6
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Rossi G, Liu KF, Kershaw H, Riddell D, Hyndman TH, Monks D, Musk GC. Biological Variation in Biochemistry Analytes in Laboratory Guinea Pigs ( Cavia porcellus). Vet Sci 2023; 10:621. [PMID: 37888573 PMCID: PMC10610888 DOI: 10.3390/vetsci10100621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 09/27/2023] [Accepted: 10/11/2023] [Indexed: 10/28/2023] Open
Abstract
Biological variation (BV) describes the physiological random fluctuation around a homeostatic set point, which is a characteristic of all blood measurands (analytes). That variation may impact the clinical relevance of the changes that are observed in the serial results for an individual. Biological variation is represented mathematically by the coefficient of variation (CV) and occurs within each individual (CVI) and between individuals in a population (CVG). Biological variation data can be used to assess whether population-based reference or subject-based reference intervals should be used for the interpretation of laboratory results through the calculation of the index of individuality (IoI). This study aimed to determine the biological variations, calculate the IoI and reference change values (RCV) of clinical chemistry analytes in an outbred strain colony of Hartley guinea pigs (GPs), and set the quality specifications for clinical chemistry analytes. Blood was collected from 16 healthy adult laboratory colony GPs via jugular venipuncture at weekly intervals over six weeks. All the samples were frozen and analyzed in a single run. Analytical, CVI, and CVG biological variations, together with the IoI and RCV, were calculated for each measurand. Based on the estimated BV, the calculated IoI was low for glucose, so individual reference intervals (RCV) should be used. The majority of the measurands should be interpreted using both population-based and subject-based reference intervals as the IoIs were intermediate.
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Affiliation(s)
- Gabriele Rossi
- School of Veterinary Medicine, Murdoch University, Murdoch, WA 6150, Australia; (K.-F.L.); (T.H.H.)
- Centre for Animal Production and Health, Murdoch University, Murdoch, WA 6150, Australia
| | - Kwei-Farn Liu
- School of Veterinary Medicine, Murdoch University, Murdoch, WA 6150, Australia; (K.-F.L.); (T.H.H.)
| | - Helen Kershaw
- Animal Care Services, University of Western Australia, Crawley, WA 6009, Australia; (H.K.); (D.R.); (G.C.M.)
| | - Dayna Riddell
- Animal Care Services, University of Western Australia, Crawley, WA 6009, Australia; (H.K.); (D.R.); (G.C.M.)
| | - Timothy H. Hyndman
- School of Veterinary Medicine, Murdoch University, Murdoch, WA 6150, Australia; (K.-F.L.); (T.H.H.)
| | - Deborah Monks
- Brisbane Bird and Exotics Veterinary Service, Greenslopes, QLD 4120, Australia;
| | - Gabrielle C. Musk
- Animal Care Services, University of Western Australia, Crawley, WA 6009, Australia; (H.K.); (D.R.); (G.C.M.)
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7
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Prieto JM, Carney PC, Smith SM, Miller ML, Rishniw M, Randolph JF, Salerno VJ, Lamb SV, Place NJ, Farace G, Peterson S, Peterson ME. Biological variation of serum thyrotropin and thyroid hormones concentrations determined at 8-week intervals for 1 year in clinically healthy cats. Vet Clin Pathol 2023; 52:493-502. [PMID: 37528445 DOI: 10.1111/vcp.13251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 02/04/2023] [Accepted: 02/23/2023] [Indexed: 08/03/2023]
Abstract
BACKGROUND Cats commonly develop thyroid disease but little is known about the long-term biological variability of serum thyroid hormone and thyrotropin (thyroid-stimulating hormone; TSH) concentrations. OBJECTIVES We aimed to determine the long-term biological variation of thyroid hormones and TSH in clinically healthy cats. METHODS A prospective, observational study was carried out. Serum samples for analysis of total thyroxine (T4, by radioimmunoassay [RIA] and homogenous enzyme immunoassay [EIA]), triiodothyronine (T3 ), free T4 (by dialysis), and TSH were obtained every 8 weeks for 1 year from 15 healthy cats, then frozen until single-batch analysis. Coefficients of variation (CV) within individual cats (CV I ) and among individual cats (CV G ), as well as the variation between duplicates (ie, analytical variation [CV A ]) were determined with restricted maximum likelihood estimation. The indices of individuality (IoI) and reference change values (RCVs) for each hormone were calculated. RESULTS Some thyroid hormones showed similar (total T4 by EIA) or greater (TSH) interindividual relative to intraindividual variation resulting in intermediate to high IoI, consistent with previous studies evaluating the biological variation of these hormones weekly for 5-6 weeks. By contrast, total T4 (by RIA) and free T4 had a low IoI. Total T3 had a high ratio ofCV A toCV I ; therefore, interindividual variation could not be distinguished from analytical variation. No seasonal variability in the hormones could be demonstrated. CONCLUSIONS Clinicians might improve the diagnosis of feline thyroid disease by establishing baseline concentrations for analytes with intermediate-high IoI (total T4, TSH) for individual cats and applying RCVs to subsequent measurements.
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Affiliation(s)
- Jennifer M Prieto
- Departments of Clinical Sciences, Cornell University, Ithaca, New York, USA
| | - Patrick C Carney
- Departments of Clinical Sciences, Cornell University, Ithaca, New York, USA
| | - Stephanie M Smith
- Departments of Clinical Sciences, Cornell University, Ithaca, New York, USA
| | - Meredith L Miller
- Departments of Clinical Sciences, Cornell University, Ithaca, New York, USA
| | - Mark Rishniw
- Departments of Clinical Sciences, Cornell University, Ithaca, New York, USA
| | - John F Randolph
- Departments of Clinical Sciences, Cornell University, Ithaca, New York, USA
| | - Valerie J Salerno
- Population Medicine & Diagnostic Sciences, Cornell University, Ithaca, New York, USA
| | - Steve V Lamb
- Population Medicine & Diagnostic Sciences, Cornell University, Ithaca, New York, USA
| | - Ned J Place
- Population Medicine & Diagnostic Sciences, Cornell University, Ithaca, New York, USA
| | | | | | - Mark E Peterson
- Departments of Clinical Sciences, Cornell University, Ithaca, New York, USA
- Animal Endocrine Clinic, New York, New York, USA
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Yılmaz Çalık G, Şeneş M. Biological variation estimates for spot urine analytes and analyte/creatinine ratios in 33 healthy subjects. Clin Chem Lab Med 2023; 61:1481-1489. [PMID: 36794468 DOI: 10.1515/cclm-2022-1290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 02/08/2023] [Indexed: 02/17/2023]
Abstract
OBJECTIVES Urine samples are frequently used in the clinical practice. In our study, we aimed to calculate the biological variations (BV) of analytes and analyte/creatinine ratios measured in spot urine. METHODS Second-morning spot urine samples were collected from 33 (16 female, 17 male) healthy volunteers once weekly for 10 weeks and analyzed in the Roche Cobas 6,000 instrument. Statistical analyzes were performed using BioVar, an online BV calculation software. The data were evaluated in terms of normality, outliers, steady state, homogeneity of the data, and BV values were obtained by analysis of variance (ANOVA). A strict protocol was established for within-subject (CVI) and between-subject (CVG) estimates for both genders. RESULTS There was a significant difference between female/male CVI estimates of all analytes except potassium, calcium and magnesium. No difference was found in CVG estimates. When the analytes that had a significant difference in CVI estimates in spot urine analytes were compared to creatinine, it was observed that the significant difference between the genders disappeared. There was no significant difference between female/male CVI and CVG estimates in all spot urine analyte/creatinine ratios. CONCLUSIONS Since the CVI estimates of analyte/creatinine ratios are lower, it would be more reasonable to use them in result reporting. Reference ranges should be used with caution, since II values of almost all parameters are between 0.6 and 1.4. The CVI detection power of our study is 1, which is the highest value.
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Affiliation(s)
- Gizem Yılmaz Çalık
- Department of Medical Biochemistry, University of Health Sciences Ankara Training and Research Hospital, Ankara, Türkiye
| | - Mehmet Şeneş
- Department of Medical Biochemistry, University of Health Sciences Ankara Training and Research Hospital, Ankara, Türkiye
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Yildiz Z, Dağdelen LK. Reference intervals for thyroid disorders calculated by indirect method and comparison with reference change values. Biochem Med (Zagreb) 2023; 33:010704. [PMID: 36627974 PMCID: PMC9807239 DOI: 10.11613/bm.2023.010704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 10/24/2022] [Indexed: 12/23/2022] Open
Abstract
Introduction The aim of the study was to calculate reference intervals (RIs) for thyroid stimulating hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3) and evaluate the clinical significance of these intervals by use of reference change values (RCV) of the analytes. Materials and methods Laboratory patient data between August and December 2021 were evaluated for the study. A total of 188,912 patients with TSH, fT4, fT3, anti-thyroid peroxidase antibodies (Anti-TPO) and anti-thyroglobulin antibodies (Anti-Tg) results were evaluated. All measurements were performed on Cobas c801 (Roche Diagnostics, Penzberg, Germany) using electrochemiluminescence immunoassay technology. Estimated RIs were compared with manufacturer's by means of RCVs of analytes. Results Thyroid stimulating hormone values didn't differ significantly by gender and age. The combined RIs for whole group (N = 28,437) was found as 0.41-4.37 mIU/mL. Free T4 values (11.6-20.1 pmol/L, N = 13,479 in male; 10.5-19.5 pmol/L, N = 17,634 female) and fT3 values (3.38-6.35 pmol/L, N = 2,516 in male; 3.39-5.99 pmol/L, N = 3,348 pmol/L in female) significantly differed by gender (P < 0.050). Both fT4 and fT3 values also showed significant differences in age subgroups comparisons. So, male and female RIs were represented separately for age subgroups. When compared with manufacturer's RIs, TSH whole group and fT4 subgroups RIs didn't exceed the analytes' RCVs, but this difference was greater for fT3. Conclusions Reference interval estimation by use of indirect method out of laboratory data may be more accurate than manufacturer provided RIs. This population based RIs evaluated using RCV of analytes may provide useful information in clinical interpretation of laboratory results.
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10
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Tuzovic M, Tang X, Francisco N, Sell A, Drew R, Paloma A, Chow J, Liang D, Heidenreich P, Salerno M, Schnittger I, Haddad F. Reference change value of global longitudinal strain in clinical practice: A test-rest quality implementation project. Echocardiography 2022; 39:1522-1531. [PMID: 36376263 DOI: 10.1111/echo.15482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 09/26/2022] [Accepted: 10/16/2022] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Reference change value (RCV) is used to assess the significance of the difference between two measurements after accounting for pre-analytic, analytic, and within-subject variability. The objective of the current study was to define the RCV for global longitudinal strain (GLS) using different semi-automated software in standard clinical practice. METHODS Using a test-retest study design, we quantified the median coefficient of variation (CV) for GLS using AutoStrain and Automated Cardiac Motion Quantification (aCMQ) by Philips. Triplane left-ventricular ejection fraction (LVEF) was measured for comparison. Multivariable regression analysis was performed to determine factors influencing test-retest CV including image quality and the presence of segmental wall motion abnormalities (WMA). RCV was reported using a standard formula assuming two standard deviations for repeated measurements; results were also translated into Bayesian probability. Total measurement variation was described in terms of its three different components: pre-analytic (acquisition), analytic (measuring variation), and within-subject (biological) variation. RESULT Of the 44 individuals who were screened, 41 had adequate quality for strain quantification. The mean age of the cohort was 56.4 ± 16.8 years, 41% female, LVEF was 55.8 ± 9.8% and the median and interquartile range for LV GLS was -17.2 [-19.3 to -14.8]%. Autostrain was more time efficient (80% less analysis time) and had a lower total median CV than aCMQ (CV = 7.4% vs. 17.6%, p < .001). The total CV was higher in patients with WMA (6.4% vs. 13.2%, p = .035). In non-segmental disease, the CV translates to a RCV of 15% (corresponding to a probability of real change of 80%). Assuming a within-subject variability of 4.0%, the component analysis identified that inter-reader variability accounts for 3.7% of the CV, while acquisition variability accounts for 4.0%. CONCLUSION Using test-retest analysis and CVs, we find that an RCV of 15% for GLS represents an optimistic estimate in routine clinical practice. Based on our results, a higher RCV of 17%-21% is needed in order to provide a high probability of clinically meaningful change in GLS in all comers. The methodology presented here for determining measurement reproducibility and RCVs is easily translatable into clinical practice for any imaging parameter.
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Affiliation(s)
- Mirela Tuzovic
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, California, USA
| | - Xiu Tang
- Echocardiography Imaging Center, Cardiovascular Heath, Stanford Health Care, Stanford, California, USA
| | - Nadia Francisco
- Echocardiography Imaging Center, Cardiovascular Heath, Stanford Health Care, Stanford, California, USA
| | - April Sell
- Echocardiography Imaging Center, Cardiovascular Heath, Stanford Health Care, Stanford, California, USA
| | - Robert Drew
- Echocardiography Imaging Center, Cardiovascular Heath, Stanford Health Care, Stanford, California, USA
| | - Allan Paloma
- Echocardiography Imaging Center, Cardiovascular Heath, Stanford Health Care, Stanford, California, USA
| | - Judy Chow
- Echocardiography Imaging Center, Cardiovascular Heath, Stanford Health Care, Stanford, California, USA
| | - David Liang
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, California, USA
| | - Paul Heidenreich
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, California, USA.,Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA
| | - Michael Salerno
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, California, USA
| | - Ingela Schnittger
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, California, USA
| | - Francois Haddad
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, California, USA
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Abstract
Using laboratory test results for diagnosis and monitoring requires a reliable reference to which the results can be compared. Currently, most reference data is derived from the population, and patients in this context are considered members of a population group rather than individuals. However, such reference data has limitations when used as the reference for an individual. A patient's test results preferably should be compared with their own, individualized reference intervals (RI), i.e. a personalized RI (prRI).The prRI is based on the homeostatic model and can be calculated using an individual's previous test results obtained in a steady-state situation and estimates of analytical (CVA) and biological variation (BV). BV used to calculate the prRI can be obtained from the population (within-subject biological variation, CVI) or an individual's own data (within-person biological variation, CVP). Statistically, the prediction interval provides a useful tool to calculate the interval (i.e. prRI) for future observation based on previous measurements. With the development of information technology, the data of millions of patients is stored and processed in medical laboratories, allowing the implementation of personalized laboratory medicine. PrRI for each individual should be made available as part of the laboratory information system and should be continually updated as new test results become available.In this review, we summarize the limitations of population-based RI for the diagnosis and monitoring of disease, provide an outline of the prRI concept and different approaches to its determination, including statistical considerations for deriving prRI, and discuss aspects which must be further investigated prior to implementation of prRI in clinical practice.
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Affiliation(s)
- Abdurrahman Coskun
- Acibadem Labmed Clinical Laboratories, Istanbul, Turkey.,Department of Medical Biochemistry, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Sverre Sandberg
- Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway.,Norwegian Porphyria Centre and Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway.,Department of Global Health and Primary Care, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway
| | - Ibrahim Unsal
- Acibadem Labmed Clinical Laboratories, Istanbul, Turkey
| | - Mustafa Serteser
- Acibadem Labmed Clinical Laboratories, Istanbul, Turkey.,Department of Medical Biochemistry, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Aasne K Aarsand
- Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway.,Norwegian Porphyria Centre and Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway
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12
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Marqués-García F, Nieto-Librero A, González-García N, Galindo-Villardón P, Martínez-Sánchez LM, Tejedor-Ganduxé X, Boned B, Muñoz-Calero M, García-Lario JV, González-Lao E, González-Tarancón R, Fernández-Fernández MP, Perich MC, Simón M, Díaz-Garzón J, Fernández-Calle P. Within-subject biological variation estimates using an indirect data mining strategy. Spanish multicenter pilot study (BiVaBiDa). Clin Chem Lab Med 2022; 60:1804-1812. [PMID: 36036462 DOI: 10.1515/cclm-2021-0863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 08/16/2022] [Indexed: 11/15/2022]
Abstract
OBJECTIVES The estimates of biological variation (BV) have traditionally been determined using direct methods, which present limitations. In response to this issue, two papers have been published addressing these limitations by employing indirect methods. Here, we present a new procedure, based on indirect methods that analyses data collected within a multicenter pilot study. Using this method, we obtain CVI estimates and calculate confidence intervals (CI), using the EFLM-BVD CVI estimates as gold standard for comparison. METHODS Data were collected over a 18-month period for 7 measurands, from 3 Spanish hospitals; inclusion criteria: patients 18-75 years with more than two determinations. For each measurand, four different strategies were carried out based on the coefficient of variation ratio (rCoeV) and based on the use of the bootstrap method (OS1, RS2 and RS3). RS2 and RS3 use symmetry reference change value (RCV) to clean database. RESULTS RS2 and RS3 had the best correlation for the CVI estimates with respect to EFLM-BVD. RS2 used the symmetric RCV value without eliminating outliers, while RS3 combined RCV and outliers. When using the rCoeV and OS1 strategies, an overestimation of the CVI value was obtained. CONCLUSIONS Our study presents a new strategy for obtaining robust CVI estimates using an indirect method together with the value of symmetric RCV to select the target population. The CVI estimates obtained show a good correlation with those published in the EFLM-BVD database. Furthermore, our strategy can resolve some of the limitations encountered when using direct methods such as calculating confidence intervals.
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Affiliation(s)
- Fernando Marqués-García
- Clinical Biochemistry Department, Metropolitan North Clinical Laboratory (LUMN), Germans Trias i Pujol University Hospital, Barcelona, Spain.,Spanish Society of Laboratory Medicine (SEQC), Analytical Quality Commission, Barcelona, Spain
| | - Ana Nieto-Librero
- Statistics Department, Medicine Faculty, University of Salamanca, Salamanca, Spain
| | | | | | - Luisa María Martínez-Sánchez
- Spanish Society of Laboratory Medicine (SEQC), Analytical Quality Commission, Barcelona, Spain.,Biochemistry Department, Clinical Laboratories and Clinical Biochemistry Group Vall d'Hebron Institute of Research, Vall d'Hebron University Hospital, Barcelona, Spain
| | - Xavier Tejedor-Ganduxé
- Clinical Biochemistry Department, Metropolitan North Clinical Laboratory (LUMN), Germans Trias i Pujol University Hospital, Barcelona, Spain.,Spanish Society of Laboratory Medicine (SEQC), Analytical Quality Commission, Barcelona, Spain
| | - Beatriz Boned
- Spanish Society of Laboratory Medicine (SEQC), Analytical Quality Commission, Barcelona, Spain.,Royo Villanova Hospital, Zaragoza, Spain
| | - María Muñoz-Calero
- Spanish Society of Laboratory Medicine (SEQC), Analytical Quality Commission, Barcelona, Spain.,Reina Sofia University Hospital, Córdoba, Spain
| | - Jose-Vicente García-Lario
- Spanish Society of Laboratory Medicine (SEQC), Analytical Quality Commission, Barcelona, Spain.,San Cecilio University Hospital, Granada, Spain
| | - Elisabet González-Lao
- Spanish Society of Laboratory Medicine (SEQC), Analytical Quality Commission, Barcelona, Spain.,Consorcio Sanitario de Terrassa, Barcelona, Spain
| | - Ricardo González-Tarancón
- Spanish Society of Laboratory Medicine (SEQC), Analytical Quality Commission, Barcelona, Spain.,Clinical Biochemistry Department, Miguel Servet University Hospital, Zaragoza, Spain
| | - M Pilar Fernández-Fernández
- Spanish Society of Laboratory Medicine (SEQC), Analytical Quality Commission, Barcelona, Spain.,Clinical Biochemistry Department, Carmen y Severo Ochoa Hospital, Cangas del Narcea, Asturias, Spain
| | - Maria Carmen Perich
- Spanish Society of Laboratory Medicine (SEQC), Analytical Quality Commission, Barcelona, Spain
| | - Margarida Simón
- Spanish Society of Laboratory Medicine (SEQC), Analytical Quality Commission, Barcelona, Spain.,Consortium of Laboratory Intercomarcal Alt Penedès and Garraf l'Anoia, Vilafranca del Penedès, Spain
| | - Jorge Díaz-Garzón
- Spanish Society of Laboratory Medicine (SEQC), Analytical Quality Commission, Barcelona, Spain.,Department of Laboratory Medicine, La Paz University Hospital, Madrid, Spain
| | - Pilar Fernández-Calle
- Spanish Society of Laboratory Medicine (SEQC), Analytical Quality Commission, Barcelona, Spain.,Department of Laboratory Medicine, La Paz University Hospital, Madrid, Spain
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13
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Ma L, Zhang B, Luo L, Shi R, Wu Y, Liu Y. Biological variation estimates obtained from Chinese subjects for 32 biochemical measurands in serum. Clin Chem Lab Med 2022; 60:1648-1660. [PMID: 35977427 DOI: 10.1515/cclm-2021-0928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 06/24/2022] [Indexed: 11/15/2022]
Abstract
OBJECTIVES The European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) have established a program of work to make available, and to enable delivery of well characterized data describing the biological variation (BV) of clinically important measurands. Guided by the EFLM work the study presented here delivers BV estimates obtained from Chinese subjects for 32 measurands in serum. METHODS Samples were drawn from 48 healthy volunteers (26 males, 22 females; age range, 21-45 years) for 5 consecutive weeks at Chinese laboratory. Sera were stored at -80 °C before triplicate analysis of all samples on a Cobas 8000 modular analyzer series. Outlier and homogeneity analyses were performed, followed by CV-ANOVA, to determine BV estimates with confidence intervals. RESULTS The within-subject biological variation (CVI) estimates for 30 of the 32 measurands studied, were lower than listed on the EFLM database; the exceptions were alanine aminotransferase (ALT), lipoprotein (a) (LP(a)). Most of the between-subject biological variation (CVG) estimates were lower than the EFLM database entries. CONCLUSIONS This study delivers BV data for a Chinese population to supplement the EFLM BV database. Population differences may have an impact on applications of BV Data.
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Affiliation(s)
- Liming Ma
- Department of Clinical Laboratory, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, P.R. China
| | - Bin Zhang
- Department of Clinical Laboratory, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, P.R. China
| | - Limei Luo
- Department of Clinical Laboratory, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, P.R. China
| | - Rui Shi
- Department of Clinical Laboratory, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, P.R. China
| | - Yonghua Wu
- Department of Clinical Laboratory, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, P.R. China
| | - Yunshuang Liu
- Department of Clinical Laboratory, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, P.R. China
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14
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Alegre E, Varo N, Fernández-Calle P, Calleja S, González Á. Impact of ultra-low temperature long-term storage on the preanalytical variability of twenty-one common biochemical analytes. Clin Chem Lab Med 2022; 60:1003-1010. [PMID: 35470640 DOI: 10.1515/cclm-2022-0063] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 04/11/2022] [Indexed: 02/04/2023]
Abstract
OBJECTIVES Retrospective studies frequently assume analytes long-term stability at ultra-low temperatures. However, these storage conditions, common among biobanks and research, may increase the preanalytical variability, adding a potential uncertainty to the measurements. This study is aimed to evaluate long-term storage stability of different analytes at <-70 °C and to assess its impact on the reference change value formula. METHODS Twenty-one analytes commonly measured in clinical laboratories were quantified in 60 serum samples. Samples were immediately aliquoted and frozen at <-70 °C, and reanalyzed after 11 ± 3.9 years of storage. A change in concentration after storage was considered relevant if the percent deviation from the baseline measurement was significant and higher than the analytical performance specifications. RESULTS Preanalytical variability (CVP) due to storage, determined by the percentage deviation, showed a noticeable dispersion. Changes were relevant for alanine aminotransferase, creatinine, glucose, magnesium, potassium, sodium, total bilirubin and urate. No significant differences were found in aspartate aminotransferase, calcium, carcinoembryonic antigen, cholesterol, C-reactive protein, direct bilirubin, free thryroxine, gamma-glutamyltransferase, lactate dehydrogenase, prostate-specific antigen, triglycerides, thyrotropin, and urea. As nonnegligible, CVP must remain included in reference change value formula, which was modified to consider whether one or two samples were frozen. CONCLUSIONS After long-term storage at ultra-low temperatures, there was a significant variation in some analytes that should be considered. We propose that reference change value formula should include the CVP when analyzing samples stored in these conditions.
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Affiliation(s)
- Estibaliz Alegre
- Service of Biochemistry, Clínica Universidad de Navarra, Pamplona, Spain.,Navarra Health Research Institute, IdiSNA, Pamplona, Spain
| | - Nerea Varo
- Service of Biochemistry, Clínica Universidad de Navarra, Pamplona, Spain.,Navarra Health Research Institute, IdiSNA, Pamplona, Spain
| | | | - Sofía Calleja
- Service of Biochemistry, Clínica Universidad de Navarra, Pamplona, Spain
| | - Álvaro González
- Service of Biochemistry, Clínica Universidad de Navarra, Pamplona, Spain.,Navarra Health Research Institute, IdiSNA, Pamplona, Spain
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15
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Alaour B, Omland T, Torsvik J, Kaier TE, Sylte MS, Strand H, Quraishi J, McGrath S, Williams L, Meex S, Redwood S, Marber M, Aakre KM. Biological variation of cardiac myosin-binding protein C in healthy individuals. Clin Chem Lab Med 2022; 60:576-583. [PMID: 34162037 DOI: 10.1515/cclm-2021-0306] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/10/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Cardiac myosin-binding protein C (cMyC) is a novel biomarker of myocardial injury, with a promising role in the triage and risk stratification of patients presenting with acute cardiac disease. In this study, we assess the weekly biological variation of cMyC, to examine its potential in monitoring chronic myocardial injury, and to suggest analytical quality specification for routine use of the test in clinical practice. METHODS Thirty healthy volunteers were included. Non-fasting samples were obtained once a week for ten consecutive weeks. Samples were tested in duplicate on the Erenna® platform by EMD Millipore Corporation. Outlying measurements and subjects were identified and excluded systematically, and homogeneity of analytical and within-subject variances was achieved before calculating the biological variability (CVI and CVG), reference change values (RCV) and index of individuality (II). RESULTS Mean age was 38 (range, 21-64) years, and 16 participants were women (53%). The biological variation, RCV and II with 95% confidence interval (CI) were: CVA (%) 19.5 (17.8-21.6), CVI (%) 17.8 (14.8-21.0), CVG (%) 66.9 (50.4-109.9), RCV (%) 106.7 (96.6-120.1)/-51.6 (-54.6 to -49.1) and II 0.42 (0.29-0.56). There was a trend for women to have lower CVG. The calculated RCVs were comparable between genders. CONCLUSIONS cMyC exhibits acceptable RCV and low II suggesting that it could be suitable for disease monitoring, risk stratification and prognostication if measured serially. Analytical quality specifications based on biological variation are similar to those for cardiac troponin and should be achievable at clinically relevant concentrations.
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Affiliation(s)
- Bashir Alaour
- King's College London BHF Centre, The Rayne Institute, St Thomas' Hospital, London, UK
| | - Torbjørn Omland
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Cardiology, Division of Medicine, Akershus University Hospital, Lørenskog, Norway
| | - Janniche Torsvik
- Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway
| | - Thomas E Kaier
- King's College London BHF Centre, The Rayne Institute, St Thomas' Hospital, London, UK
| | - Marit S Sylte
- Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway
| | - Heidi Strand
- Multidisciplinary Laboratory Medicine and Medical Biochemistry, Akershus University Hospital, Lørenskog, Norway
| | - Jasmine Quraishi
- King's College London BHF Centre, The Rayne Institute, St Thomas' Hospital, London, UK
| | | | | | - Steven Meex
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center (MUMC), Maastricht, The Netherlands
| | - Simon Redwood
- King's College London BHF Centre, The Rayne Institute, St Thomas' Hospital, London, UK
| | - Michael Marber
- King's College London BHF Centre, The Rayne Institute, St Thomas' Hospital, London, UK
| | - Kristin M Aakre
- Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway
- Department of Heart Disease, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
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16
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Dittadi R, Fabricio ASC, Gion M. Biological variation and reference change value as decision criteria in clinical use of tumor biomarkers. Are they really useful? Clin Chem Lab Med 2022; 60:e136-e137. [PMID: 35263822 DOI: 10.1515/cclm-2022-0047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 02/23/2022] [Indexed: 11/15/2022]
Affiliation(s)
- Ruggero Dittadi
- Laboratory Medicine Unit, Department of Clinical Pathology, Ospedale dell'Angelo, Azienda ULSS 3 Serenissima, Mestre, Venice, Italy.,Regional Center for Biomarkers, Department of Clinical Pathology, Azienda ULSS 3 Serenissima, Venice, Italy
| | | | - Massimo Gion
- Regional Center for Biomarkers, Department of Clinical Pathology, Azienda ULSS 3 Serenissima, Venice, Italy
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17
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Cembrowski GS, Lyon AW, McCudden C, Qiu Y, Xu Q, Mei J, Tran DV, Sadrzadeh SMH, Cervinski MA. Transformation of Sequential Hospital and Outpatient Laboratory Data into Between-Day Reference Change Values. Clin Chem 2022; 68:595-603. [PMID: 35137000 DOI: 10.1093/clinchem/hvab271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 11/15/2021] [Indexed: 11/14/2022]
Abstract
BACKGROUND Serial differences between intrapatient consecutive measurements can be transformed into Taylor series of variation vs time with the intersection at time = 0 (y0) equal to the total variation (analytical + biological + preanalytical). With small preanalytical variation, y0, expressed as a percentage of the mean, is equal to the variable component of the reference change value (RCV) calculation: (CVA2 + CVI2)1/2. METHODS We determined the between-day RCV of patient data for 17 analytes and compared them to healthy participants' RCVs. We analyzed 653 consecutive days of Dartmouth-Hitchcock Roche Modular general chemistry data (4.2 million results: 60% inpatient, 40% outpatient). The serial patient values of 17 analytes were transformed into 95% 2-sided RCV (RCVAlternate), and 3 sets of RCVhealthy were calculated from 3 Roche Modular analyzers' quality control summaries and CVI derived from biological variation (BV) studies using healthy participants. RESULTS The RCVAlternate values are similar to RCVhealthy derived from known components of variation. For sodium, chloride, bicarbonate calcium, magnesium, phosphate, alanine aminotransferase, albumin, and total protein, the RCVs are equivalent. As expected, increased variation was found for glucose, aspartate aminotransferase, creatinine, and potassium. Direct bilirubin and urea demonstrated lower variation. CONCLUSIONS Our RCVAlternate values integrate known and unknown components of analytic, biologic, and preanalytic variation, and depict the variations observed by clinical teams that make medical decisions based on the test values. The RCVAlternate values are similar to the RCVhealthy values derived from known components of variation and suggest further studies to better understand the results being generated on actual patients tested in typical laboratory environments.
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Affiliation(s)
- George S Cembrowski
- Faculty of Medicine & Dentistry, Laboratory Medicine and Pathology, University of Alberta, Alberta, Canada
| | - Andrew W Lyon
- Saskatoon Health Region, Pathology and Laboratory Medicine, Saskatoon, Canada
| | - Christopher McCudden
- Department of Pathology & Laboratory Medicine, University of Ottawa Faculty of Medicine, Ottawa, Canada
| | - Yuelin Qiu
- Medical Student, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Qian Xu
- Family Practice, Vancouver, British Columbia
| | - Junyi Mei
- Faculty of Medicine, University of Toronto, Toronto, Canada
| | | | - S M Hossein Sadrzadeh
- Laboratory Medicine, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Mark A Cervinski
- Laboratory Medicine, Geisel School of Medicine, Dartmouth, NH, USA
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18
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Wang S, Zhao M, Su Z, Mu R. Annual biological variation and personalized reference intervals of clinical chemistry and hematology analytes. Clin Chem Lab Med 2021; 60:606-617. [PMID: 34773728 DOI: 10.1515/cclm-2021-0479] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 10/28/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES A large number of people undergo annual health checkup but accurate laboratory criterion for evaluating their health status is limited. The present study determined annual biological variation (BV) and derived parameters of common laboratory analytes in order to accurately evaluate the test results of the annual healthcare population. METHODS A total of 43 healthy individuals who had regular healthcare once a year for six consecutive years, were enrolled using physical, electrocardiogram, ultrasonography and laboratory. The annual BV data and derived parameters, such as reference change value (RCV) and index of individuality (II) were calculated and compared with weekly data. We used annual BV and homeostatic set point to calculate personalized reference intervals (RIper) which were compared with population-based reference intervals (RIpop). RESULTS We have established the annual within-subject BV (CVI), RCV, II, RIper of 24 commonly used clinical chemistry and hematology analytes for healthy individuals. Among the 18 comparable measurands, CVI estimates of annual data for 11 measurands were significantly higher than the weekly data. Approximately 50% measurands of II were <0.6, the utility of their RIpop were limited. The distribution range of RIper for most measurands only copied small part of RIpop with reference range index for 8 measurands <0.5. CONCLUSIONS Compared with weekly BV, for annual healthcare individuals, annual BV and related parameters can provide more accurate evaluation of laboratory results. RIper based on long-term BV data is very valuable for "personalized" diagnosis on annual health assessments.
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Affiliation(s)
- Shuo Wang
- Department of Laboratory Medicine, The First Hospital of China Medical University, National Clinical Research Center for Laboratory Medicine, Shenyang, Liaoning, P.R. China
| | - Min Zhao
- Department of Laboratory Medicine, The First Hospital of China Medical University, National Clinical Research Center for Laboratory Medicine, Shenyang, Liaoning, P.R. China
| | - Zihan Su
- Department of Laboratory Medicine, The First Hospital of China Medical University, National Clinical Research Center for Laboratory Medicine, Shenyang, Liaoning, P.R. China
| | - Runqing Mu
- Department of Laboratory Medicine, The First Hospital of China Medical University, National Clinical Research Center for Laboratory Medicine, Shenyang, Liaoning, P.R. China
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19
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van Rossum HH, Meng QH, Ramanathan LV, Holdenrieder S. A word of caution on using tumor biomarker reference change values to guide medical decisions and the need for alternatives. Clin Chem Lab Med 2021; 60:553-555. [PMID: 34648697 DOI: 10.1515/cclm-2021-0933] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 09/13/2021] [Indexed: 12/13/2022]
Affiliation(s)
- Huub H van Rossum
- Department of Laboratory Medicine, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Qing H Meng
- Department of Laboratory Medicine, Division of Pathology and Laboratory Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Lakshmi V Ramanathan
- Clinical Chemistry Service, Department of Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Stefan Holdenrieder
- Institute of Laboratory Medicine, Munich Biomarker Research Center, Deutsches Herzzentrum München, Technische Universität Munchen, Munich, Germany
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20
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Shi J, Mu RQ, Wang P, Geng WQ, Jiang YJ, Zhao M, Shang H, Zhang ZN. The development of autoverification system of lymphocyte subset assays on the flow cytometry platform. Clin Chem Lab Med 2021; 60:92-100. [PMID: 34533003 DOI: 10.1515/cclm-2021-0736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 09/04/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Peripheral blood lymphocyte subsets are important parameters for monitoring immune status; however, lymphocyte subset detection is time-consuming and error-prone. This study aimed to explore a highly efficient and clinically useful autoverification system for lymphocyte subset assays performed on the flow cytometry platform. METHODS A total of 94,402 lymphocyte subset test results were collected. To establish the limited-range rules, 80,427 results were first used (69,135 T lymphocyte subset tests and 11,292 NK, B, T lymphocyte tests), of which 15,000 T lymphocyte subset tests from human immunodeficiency virus (HIV) infected patients were used to set customized limited-range rules for HIV infected patients. Subsequently, 13,975 results were used for historical data validation and online test validation. RESULTS Three key autoverification rules were established, including limited-range, delta-check, and logical rules. Guidelines for addressing the issues that trigger these rules were summarized. The historical data during the validation phase showed that the total autoverification passing rate of lymphocyte subset assays was 69.65% (6,941/9,966), with a 67.93% (5,268/7,755) passing rate for T lymphocyte subset tests and 75.67% (1,673/2,211) for NK, B, T lymphocyte tests. For online test validation, the total autoverification passing rate was 75.26% (3,017/4,009), with 73.23% (2,191/2,992) for the T lymphocyte subset test and 81.22% (826/1,017) for the NK, B, T lymphocyte test. The turnaround time (TAT) was reduced from 228 to 167 min using the autoverification system. CONCLUSIONS The autoverification system based on the laboratory information system for lymphocyte subset assays reduced TAT and the number of error reports and helped in the identification of abnormal cell populations that may offer clues for clinical interventions.
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Affiliation(s)
- Jue Shi
- NHC Key Laboratory of AIDS Immunology (China Medical University), National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang, P. R. China.,Key Laboratory of AIDS Immunology, Chinese Academy of Medical Sciences, Shenyang, P. R. China
| | - Run-Qing Mu
- Department of Laboratory Medicine, National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang, P. R. China
| | - Pan Wang
- NHC Key Laboratory of AIDS Immunology (China Medical University), National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang, P. R. China.,Key Laboratory of AIDS Immunology, Chinese Academy of Medical Sciences, Shenyang, P. R. China
| | - Wen-Qing Geng
- NHC Key Laboratory of AIDS Immunology (China Medical University), National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang, P. R. China.,Key Laboratory of AIDS Immunology, Chinese Academy of Medical Sciences, Shenyang, P. R. China
| | - Yong-Jun Jiang
- NHC Key Laboratory of AIDS Immunology (China Medical University), National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang, P. R. China.,Key Laboratory of AIDS Immunology, Chinese Academy of Medical Sciences, Shenyang, P. R. China
| | - Min Zhao
- Department of Laboratory Medicine, National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang, P. R. China
| | - Hong Shang
- NHC Key Laboratory of AIDS Immunology (China Medical University), National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang, P. R. China.,Key Laboratory of AIDS Immunology, Chinese Academy of Medical Sciences, Shenyang, P. R. China.,Department of Laboratory Medicine, National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang, P. R. China
| | - Zi-Ning Zhang
- NHC Key Laboratory of AIDS Immunology (China Medical University), National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang, P. R. China.,Key Laboratory of AIDS Immunology, Chinese Academy of Medical Sciences, Shenyang, P. R. China
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21
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Aarsand AK, Kristoffersen AH, Sandberg S, Støve B, Coşkun A, Fernandez-Calle P, Díaz-Garzón J, Guerra E, Ceriotti F, Jonker N, Røraas T, Carobene A. The European Biological Variation Study (EuBIVAS): Biological Variation Data for Coagulation Markers Estimated by a Bayesian Model. Clin Chem 2021; 67:1259-1270. [PMID: 34387652 DOI: 10.1093/clinchem/hvab100] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/19/2021] [Indexed: 11/13/2022]
Abstract
BACKGROUND For biological variation (BV) data to be safely used, data must be reliable and relevant to the population in which they are applied. We used samples from the European Biological Variation Study (EuBIVAS) to determine BV of coagulation markers by a Bayesian model robust to extreme observations and used the derived within-participant BV estimates [CVP(i)] to assess the applicability of the BV estimates in clinical practice. METHOD Plasma samples were drawn from 92 healthy individuals for 10 consecutive weeks at 6 European laboratories and analyzed in duplicate for activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen, D-dimer, antithrombin (AT), protein C, protein S free, and factor VIII (FVIII). A Bayesian model with Student t likelihoods for samples and replicates was applied to derive CVP(i) and predicted BV estimates with 95% credibility intervals. RESULTS For all markers except D-dimer, CVP(i) were homogeneously distributed in the overall study population or in subgroups. Mean within-subject estimates (CVI) were <5% for APTT, PT, AT, and protein S free, <10% for protein C and FVIII, and <12% for fibrinogen. For APTT, protein C, and protein S free, estimates were significantly lower in men than in women ≤50 years. CONCLUSION For most coagulation markers, a common CVI estimate for men and women is applicable, whereas for APTT, protein C, and protein S free, sex-specific reference change values should be applied. The use of a Bayesian model to deliver individual CVP(i) allows for improved interpretation and application of the data.
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Affiliation(s)
- Aasne K Aarsand
- Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway.,Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway
| | - Ann Helen Kristoffersen
- Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway.,Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway
| | - Sverre Sandberg
- Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway.,Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway.,Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
| | - Bård Støve
- Department of Mathematics, University of Bergen, Bergen, Norway
| | - Abdurrahman Coşkun
- Department of Medical Biochemistry, Acibadem Mehmet Ali Aydınlar University School of Medicine, Atasehir, Istanbul, Turkey
| | - Pilar Fernandez-Calle
- Department of Laboratory Medicine, Hospital Universitario La Paz, Madrid, Spain.,Analytical Quality Commission of Spanish Society of Laboratory Medicine (SEQCML), Madrid, Spain
| | - Jorge Díaz-Garzón
- Department of Laboratory Medicine, Hospital Universitario La Paz, Madrid, Spain.,Analytical Quality Commission of Spanish Society of Laboratory Medicine (SEQCML), Madrid, Spain
| | - Elena Guerra
- Laboratory Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Ferruccio Ceriotti
- Central Laboratory, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Niels Jonker
- Certe, Wilhelmina Ziekenhuis Assen, Assen, the Netherlands
| | - Thomas Røraas
- Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway
| | - Anna Carobene
- Laboratory Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy
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22
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Abstract
For more than one half-century, variability observed in clinical test result measurements has been ascribed to three major independent factors: (i) pre-analytical variation, occurring at sample collection and processing steps; (ii) analytical variation of the test method for which measurements are taken, and; (iii) biological variation (BV). Appreciation of this last source of variability is the major goal of this review article. Several recent advances have been made to generate, collate, and utilize BV data of biomarker tests within the clinical laboratory setting. Consideration of both prospective and retrospective study designs will be addressed. The prospective/direct study design will be described in accordance with recent recommendations discussed in the framework of a newly-developed system of checklist items. Potential value of retrospective/indirect study design, modeled on data mining from cohort studies or pathology laboratory information systems (LIS), offers an alternative approach to obtain BV estimates for clinical biomarkers. Moreover, updates to BV databases have made these data more current and widely accessible. Principal aims of this review are to provide the clinical laboratory scientist with a historical framework of BV concepts, to highlight useful applications of BV data within the clinical laboratory environment, and to discuss key terms and concepts related to statistical treatment of BV data.
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Affiliation(s)
- Paul R Johnson
- Department of Clinical Laboratory Science, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Shahram Shahangian
- Division of Laboratory Systems, US Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - J Rex Astles
- Division of Laboratory Systems, US Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
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23
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Mairesse A, Wauthier L, Courcelles L, Luyten U, Burlacu MC, Maisin D, Favresse J, van Dievoet MA, Gruson D. Biological variation and analytical goals of four thyroid function biomarkers in healthy European volunteers. Clin Endocrinol (Oxf) 2021; 94:845-850. [PMID: 33107075 DOI: 10.1111/cen.14356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/30/2020] [Accepted: 10/05/2020] [Indexed: 11/29/2022]
Abstract
BACKGROUND Interpretation of thyroid function tests by means of biological variation (BV) data is essential to identify significant changes between serial measurements at an individual level. Data on thyroid parameters in adults are limited. OBJECTIVES We aimed at determining the BV of four thyroid function test (thyroid-stimulating hormone (TSH), free thyroxin (FT4), free triiodothyronine (FT3) and thyroglobulin (Tg)) by applying recent recommendations to acquire BV data on a latest generation of immunoassay. METHODS Nineteen healthy volunteers (8 males and 11 females) were drawn every week during 5 consecutive weeks. Samples were analysed in duplicate on the Cobas 602 analyzer (Roche Diagnostics). After normality assessment, outlier exclusion and homogeneity of variance analysis, analytical variation (CVA ), within-subject biological variation (CVI ) and between-subject biological variation (CVG ) were determined using nested ANOVA. RESULTS CVA , CVI and CVG were 0.9%, 19.7% and 37.6% for TSH; 3.6%, 4.6% and 10.8% for FT4; 2.2%, 6.0% and 8.6% for FT3; and 0.9%, 15.4% and 84.9% for Tg. Index of individuality (II) for all parameters was between 0.2 and 0.7. The percentage above which the change between two measures is truly significant (reference change value) was 54.7% for TSH, 16.2% for FT4, 17.7% for FT3 and 42.8% for Tg. CONCLUSION Based on recent international recommendations, our study provides updated BV data for four thyroid function tests in European healthy volunteers. Reliable BV characteristics, and especially RCV, can facilitate the interpretation of consecutive thyroid function tests in an individual and therefore have the potential to efficiently support clinical decisions regarding thyroid diseases.
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Affiliation(s)
- Antoine Mairesse
- Clinical Biology Department, Cliniques Universitaires St Luc, Université catholique de Louvain, Brussels, Belgium
| | - Loris Wauthier
- Clinical Biology Department, Cliniques Universitaires St Luc, Université catholique de Louvain, Brussels, Belgium
| | - Louisiane Courcelles
- Clinical Biology Department, Cliniques Universitaires St Luc, Université catholique de Louvain, Brussels, Belgium
| | - Urszula Luyten
- Clinical Biology Department, Cliniques Universitaires St Luc, Université catholique de Louvain, Brussels, Belgium
| | - Maria-Cristina Burlacu
- Department of Endocrinology and Nutrition, Cliniques Universitaires St-Luc, Universite Catholique de Louvain, Brussels, Belgium
| | - Diane Maisin
- Clinical Biology Department, Cliniques Universitaires St Luc, Université catholique de Louvain, Brussels, Belgium
| | - Julien Favresse
- Department of Laboratory Medicine, Clinique St-Luc Bouge, Namur, Belgium
- Department of Pharmacy, Namur Research Institute for Life Sciences, University of Namur, Belgium
| | - Marie-Astrid van Dievoet
- Clinical Biology Department, Cliniques Universitaires St Luc, Université catholique de Louvain, Brussels, Belgium
| | - Damien Gruson
- Clinical Biology Department, Cliniques Universitaires St Luc, Université catholique de Louvain, Brussels, Belgium
- Pôle de recherche en Endocrinologie, Diabète et Nutrition, Institut de Recherche Expérimentale et Clinique, Cliniques Universitaires St-Luc and Université Catholique de Louvain, Brussels, Belgium
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24
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Bottani M, Aarsand AK, Banfi G, Locatelli M, Coşkun A, Díaz-Garzón J, Fernandez-Calle P, Sandberg S, Ceriotti F, Carobene A. European Biological Variation Study (EuBIVAS): within- and between-subject biological variation estimates for serum thyroid biomarkers based on weekly samplings from 91 healthy participants. Clin Chem Lab Med 2021; 60:523-532. [PMID: 33561908 DOI: 10.1515/cclm-2020-1885] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 01/25/2021] [Indexed: 12/17/2022]
Abstract
OBJECTIVES Thyroid biomarkers are fundamental for the diagnosis of thyroid disorders and for the monitoring and treatment of patients with these diseases. The knowledge of biological variation (BV) is important to define analytical performance specifications (APS) and reference change values (RCV). The aim of this study was to deliver BV estimates for thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), thyroglobulin (TG), and calcitonin (CT). METHODS Analyses were performed on serum samples obtained from the European Biological Variation Study population (91 healthy individuals from six European laboratories; 21-69 years) on the Roche Cobas e801 at the San Raffaele Hospital (Milan, Italy). All samples from each individual were evaluated in duplicate within a single run. The BV estimates with 95% CIs were obtained by CV-ANOVA, after analysis of variance homogeneity and outliers. RESULTS The within-subject (CV I ) BV estimates were for TSH 17.7%, FT3 5.0%, FT4 4.8%, TG 10.3, and CT 13.0%, all significantly lower than those reported in the literature. No significant differences were observed for BV estimates between men and women. CONCLUSIONS The availability of updated, in the case of CT not previously published, BV estimates for thyroid markers based on the large scale EuBIVAS study allows for refined APS and associated RCV applicable in the diagnosis and management of thyroid and related diseases.
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Affiliation(s)
- Michela Bottani
- IRCCS Istituto Ortopedico Galeazzi, Laboratory of Experimental Biochemistry & Molecular Biology, Milan, Italy
| | - Aasne K Aarsand
- Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway.,Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway
| | - Giuseppe Banfi
- IRCCS Istituto Ortopedico Galeazzi, Laboratory of Experimental Biochemistry & Molecular Biology, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
| | - Massimo Locatelli
- Laboratory Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Abdurrahman Coşkun
- School of Medicine, Acibadem Mehmet Ali Aydınlar University, Istanbul, Turkey
| | - Jorge Díaz-Garzón
- Hospital Universitario La Paz, Madrid, Spain.,Quality Analytical Commission of Spanish Society of Clinical Chemistry (SEQC), Barcelona, Spain
| | - Pilar Fernandez-Calle
- Hospital Universitario La Paz, Madrid, Spain.,Quality Analytical Commission of Spanish Society of Clinical Chemistry (SEQC), Barcelona, Spain
| | - Sverre Sandberg
- Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway.,Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway.,Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
| | - Ferruccio Ceriotti
- Clinical Laboratory, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Anna Carobene
- Laboratory Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy
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25
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Summers S, Quimby J, Yao L, Hess A, Broeckling C, Lappin M. Biological variation of major gut-derived uremic toxins in the serum of healthy adult cats. J Vet Intern Med 2021; 35:902-911. [PMID: 33537991 PMCID: PMC7995407 DOI: 10.1111/jvim.16043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 12/30/2020] [Accepted: 01/15/2021] [Indexed: 02/06/2023] Open
Abstract
Background Biological variation of serum indoxyl sulfate (IS), p‐cresol sulfate (pCS), and trimethylamine‐n‐oxide (TMAO) concentrations in cats is unknown. Objectives To determine short‐ and medium‐term biological variation, index of individuality (II), and reference change values for serum IS, pCS, and TMAO concentrations in healthy adult cats. To determine the effect of feeding on serum concentrations. Animals Twelve healthy adult cats. Methods Prospective, cohort study. Seven serum samples over a 12‐hour period (short‐term) and 5 serum samples over a 19‐day period (medium‐term) were collected. Serum concentrations of total IS, pCS, and TMAO were measured every 2 hours in a 12‐hour period (hours 0‐12) after a meal in 9 cats and compared to concentrations in a nonfed state. Results For IS, the II was high using short‐term (1.96) and low using medium‐term (0.65) biological variation estimates. Individuality was intermediate for pCS (short‐term, 0.98; medium‐term, 1.17) and TMAO (short‐term, 1.47; medium‐term, 0.83). Serum IS, pCS, and TMAO concentrations were significantly lower in a fed state compared to a nonfed state at hours 4, 6, 8, and 12; at hours 4 and 6; and at hours 2, 4, 6, 8, 10, 12, respectively. Conclusion and Clinical Importance Population‐based reference intervals with reference to the subject‐based interval can be used to monitor serum pCS and TMAO concentrations. For IS, a subject‐based and a population‐based reference interval is best for short‐term and medium‐term monitoring, respectively. To compare serial measurements, it would be prudent to collect samples at the same time of day and consistently in either a fed or nonfed state.
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Affiliation(s)
- Stacie Summers
- Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
| | | | - Linxing Yao
- Colorado State University, Fort Collins, Colorado, USA
| | - Ann Hess
- Colorado State University, Fort Collins, Colorado, USA
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26
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Hirabayashi Y, Tsukada Y, Sakurai T, Ohno H, Kizaki T. Comparative evaluation of methods to determine intra-individual reference ranges in nutrition support team (NST)-related tests. J Clin Lab Anal 2021; 35:e23639. [PMID: 33107085 PMCID: PMC7891514 DOI: 10.1002/jcla.23639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/25/2020] [Accepted: 10/09/2020] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND The intra-individual reference range is generally narrower than the commonly used reference range. Consequently, close monitoring of changes in the laboratory test results of individuals based on the inter-individual reference range remains challenging. METHODS We examined the determination of individual reference ranges using four indicators of nutritional conditions: transferrin (TRF), albumin (ALB), retinol-binding protein (RBP), and transthyretin (TTR). The subjects comprised 20 healthy individuals and blood samples were collected and tested five times at 2-week intervals. We used the measurement results for the four indicators and examined individual reference ranges using four methods, including calculation methods based on the reference change value and Bayesian inference. RESULTS The resulting intra-individual reference ranges were narrower than the currently used inter-individual reference range for all measurements using four methods. Furthermore, the intra-individual coefficient of variation [CV (intra)] was smaller than the inter-individual coefficient of variation [CV (inter)] for TRF, RBP, and TTR for all 20 subjects. The means CV (intra) for the four indicators were also lower than the corresponding CV (inter). CONCLUSIONS The intra-individual reference range can be used to validate the standard deviation and coefficient of variation for currently used indicators. Moreover, Bayesian methods are speculated to be the most versatile.
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Affiliation(s)
- Yoji Hirabayashi
- Clinical Laboratory Testing DivisionSRL Hachiohji LaboratoriesSRL, IncTokyoJapan
- Department of Molecular Predictive Medicine and Sport ScienceSchool of MedicineKyorin UniversityTokyoJapan
| | - Yutaka Tsukada
- Clinical Laboratory Testing DivisionSRL Hachiohji LaboratoriesSRL, IncTokyoJapan
| | - Takuya Sakurai
- Department of Molecular Predictive Medicine and Sport ScienceSchool of MedicineKyorin UniversityTokyoJapan
| | - Hideki Ohno
- Social Medical CorporationThe Yamatokai FoundationTokyoJapan
| | - Takako Kizaki
- Department of Molecular Predictive Medicine and Sport ScienceSchool of MedicineKyorin UniversityTokyoJapan
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27
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Emre HO, Karpuzoglu FH, Coskun C, Sezer ED, Ozturk OG, Ucar F, Cubukcu HC, Arslan FD, Deniz L, Senes M, Serteser M, Yazici C, Yucel D, Coskun A. Utilization of biological variation data in the interpretation of laboratory test results - survey about clinicians' opinion and knowledge. Biochem Med (Zagreb) 2020; 31:010705. [PMID: 33380892 PMCID: PMC7745156 DOI: 10.11613/bm.2021.010705] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 10/02/2020] [Indexed: 12/18/2022] Open
Abstract
Introduction To interpret test results correctly, understanding of the variations that affect test results is essential. The aim of this study is: 1) to evaluate the clinicians’ knowledge and opinion concerning biological variation (BV), and 2) to investigate if clinicians use BV in the interpretation of test results. Materials and methods This study uses a questionnaire comprising open-ended and close-ended questions. Questions were selected from the real-life numerical examples of interpretation of test results, the knowledge about main sources of variations in laboratories and the opinion of clinicians on BV. A total of 399 clinicians were interviewed, and the answers were evaluated using a scoring system ranked from A (clinician has the highest level of knowledge and the ability of using BV data) to D (clinician has no knowledge about variations in laboratory). The results were presented as number (N) and percentage (%). Results Altogether, 60.4% of clinicians have knowledge of pre-analytical and analytical variations; but only 3.5% of them have knowledge related to BV. The number of clinicians using BV data or reference change value (RCV) to interpret measurements results was zero, while 79.4% of clinicians accepted that the difference between two measurements results located within the reference interval may be significant. Conclusions Clinicians do not use BV data or tools derived from BV such as RCV to interpret test results. It is recommended that BV should be included in the medical school curriculum, and clinicians should be encouraged to use BV data for safe and valid interpretation of test results.
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Affiliation(s)
- Humeyra Ozturk Emre
- Department of Medical Biochemistry, Kahramanmaras Necip Fazil City Hospital, Kahramanmaras, Turkey
| | - Fatma Hande Karpuzoglu
- Department of Medical Biochemistry, Acibadem Labmed Clinical Laboratories, Istanbul, Turkey
| | - Cihan Coskun
- Department of Medical Biochemistry, Haydarpasa Training and Research Hospital, Istanbul, Turkey
| | - Ebru Demirel Sezer
- Department of Medical Biochemistry and Metabolism Laboratory, Faculty of Medicine, Ege University, Izmir, Turkey
| | | | - Fatma Ucar
- Department of Clinical Biochemistry, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
| | - Hikmet Can Cubukcu
- Department of Medical Biochemistry, Maresal Cakmak State Hospital, Erzurum, Turkey
| | - Fatma Demet Arslan
- Department of Medical Biochemistry, University of Health Sciences, Tepecik Training and Research Hospital, Izmir, Turkey
| | - Levent Deniz
- Department of Medical Biochemistry, University of Health Sciences, Istanbul Training and Research Hospital, Istanbul, Turkey
| | - Mehmet Senes
- Department of Medical Biochemistry, University of Health Sciences, Ankara Training and Research Hospital, Ankara, Turkey
| | - Mustafa Serteser
- Department of Medical Biochemistry, School of Medicine, Acıbadem Mehmet Ali Aydınlar University, Istanbul, Turkey
| | - Cevat Yazici
- Department of Medical Biochemistry, Faculty of Medicine, Erciyes University, Kayseri, Turkey
| | - Dogan Yucel
- Department of Medical Biochemistry, University of Health Sciences, Ankara Training and Research Hospital, Ankara, Turkey
| | - Abdurrahman Coskun
- Department of Medical Biochemistry, School of Medicine, Acıbadem Mehmet Ali Aydınlar University, Istanbul, Turkey
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Hong J, Cho E, Kim H, Lee W, Chun S, Min W. Application and optimization of reference change values for Delta Checks in clinical laboratory. J Clin Lab Anal 2020; 34:e23550. [PMID: 32862477 PMCID: PMC7755783 DOI: 10.1002/jcla.23550] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/23/2020] [Accepted: 08/06/2020] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Delta check is a patient-based QC tool for detecting errors by comparing current and previous test results of patient. Reference change value (RCV) is adopted in guidelines as method for delta check, but the performance is not verified. We applied RCV-based delta check method to patients' data and modified for application. MATERIALS AND METHODS Reference change value were calculated using results of internal QC materials and biological variation data. Test results of 17 analytes in inpatients, outpatients, and health examination recipients were collected. The detection rates of currently used delta check method and those of RCV-based method were compared, and the methods were modified. RESULTS Reference change value-based method had higher detection rates compared to conventional method. Applied modifications reduced detection rates. Removing the pairs of results within reference interval reduced detection rates (0.42% ~ 10.92%). When RCV was divided by time interval, the detection rates were similar to prior rates in outpatients (0.19% ~ 1.34%). Using RCV multiplied by twice the upper limit of reference value as cutoff reduced the detection rate (0.07% ~ 1.58%). CONCLUSIONS Reference change value is a robust criterion for delta check and included in clinical laboratory practice guideline. However, RCV-based method generates high detection rates which increase workload. It needs modification for use in clinical laboratories.
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Affiliation(s)
- Jinyoung Hong
- Department of Laboratory MedicineAsan Medical Center, University of Ulsan College of MedicineSeoulKorea
| | - Eun‐Jung Cho
- Department of Laboratory MedicineHallym University Dongtan Sacred Heart Hospital, Hallym University College of MedicineHwaseong‐siKorea
| | - Hyun‐Ki Kim
- Department of Laboratory MedicineUlsan University Hospital, University of Ulsan College of MedicineUlsanKorea
| | - Woochang Lee
- Department of Laboratory MedicineAsan Medical Center, University of Ulsan College of MedicineSeoulKorea
| | - Sail Chun
- Department of Laboratory MedicineAsan Medical Center, University of Ulsan College of MedicineSeoulKorea
| | - Won‐Ki Min
- Department of Laboratory MedicineAsan Medical Center, University of Ulsan College of MedicineSeoulKorea
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29
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Mairesse A, Bayart JL, Desmet S, Lopes Dos Santos H, Saussoy P, Defour JP, Eeckhoudt S, van Dievoet MA. Biological variation data and analytical specification goal estimates of the thrombin generation assay with and without thrombomodulin in healthy individuals. Int J Lab Hematol 2020; 43:450-457. [PMID: 33185328 DOI: 10.1111/ijlh.13388] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 10/15/2020] [Accepted: 10/19/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND Evaluation of an individual's thrombin-generating capacity enables a global assessment of the coagulation cascade and is therefore thought to better reflect the clotting function of blood. However, the lack of standardization still hampers the use in routine clinical practice. METHODS Nineteen healthy subjects were sampled once a week for 5 consecutive weeks. Thrombin generation assay (TGA) was performed in duplicate by calibrated automated thrombogram (CAT) on platelet poor plasma with and without thrombomodulin. After exclusion of outliers, a nested analysis of variance (ANOVA) was performed to evaluate the biological variability (BV) results. Analytical variation (CVA ), within-individual variation (CVI ), between-individual variation (CVG ), index of individuality (II), and reference change value (RCV) were calculated. RESULTS All parameters taken together, the CVA, CVI , and CVG without TM, ranged from 2.8% to 6.5%, from 4.1% to 13.3% and from 10.4% to 28.4%, respectively. For TG with TM, CVI and CVG were higher and ranged from 5.0% to 18.1% and from 14.9% to 35.3%, respectively. For endogenous thrombin potential (ETP), a CVI of 4.1% and CVG of 10.4% were obtained without addition of thrombomodulin (TM). With addition of TM, both CVI and CVG were higher: 14.0% and 34.8%, respectively. The II was low and the RCV ranged from 17.2% to 50.4%. CONCLUSION CAT parameters are highly individualized and population-based reference values could be called into question. The assessment of BV and RCV for thrombin generation assays could optimize interpretation of serial patient results and guide setting of analytical specification goals.
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Affiliation(s)
- Antoine Mairesse
- Département des Laboratoires Cliniques, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Jean-Louis Bayart
- Département des Laboratoires Cliniques, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Sandrine Desmet
- Département des Laboratoires Cliniques, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Helder Lopes Dos Santos
- Département des Laboratoires Cliniques, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Pascale Saussoy
- Département des Laboratoires Cliniques, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Jean-Philippe Defour
- Département des Laboratoires Cliniques, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Stéphane Eeckhoudt
- Département des Laboratoires Cliniques, Cliniques Universitaires Saint-Luc, Brussels, Belgium
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30
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Flatland B, Baral RM, Freeman KP. Current and emerging concepts in biological and analytical variation applied in clinical practice. J Vet Intern Med 2020; 34:2691-2700. [PMID: 33085151 PMCID: PMC7694803 DOI: 10.1111/jvim.15929] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/21/2020] [Accepted: 09/25/2020] [Indexed: 12/31/2022] Open
Abstract
A single laboratory result actually represents a range of possible values, and a given laboratory result is impacted not just by the presence or absence of disease, but also by biological variation of the measurand in question and analytical variation of the equipment used to make the measurement. Biological variation refers to variability in measurand concentration or activity around a homeostatic set point. Knowledge of biological and analytical variation can be used to facilitate interpretation of patient clinicopathologic data and is particularly useful for interpreting serial patient data and data at or near reference limits or clinical decision thresholds. Understanding how biological and analytical variation impact laboratory results is of increasing importance, because veterinarians evaluate serial data from individual patients, interpret data from multiple testing sites, and use expert consensus guidelines that include decision thresholds for clinicopathologic data interpretation. The purpose of our report is to review current and emerging concepts in biological and analytical variation and discuss how biological and analytical variation data can be used to facilitate clinicopathologic data interpretation. Inclusion of veterinary clinical pathologists having expertise in laboratory quality management and biological variation on research teams and veterinary practice guideline development teams is recommended, to ensure that various considerations for clinicopathologic data interpretation are addressed.
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Affiliation(s)
- Bente Flatland
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, USA
| | | | - Kathleen P Freeman
- Syn Laboratories - Veterinary Pathology Group (VPG), Torrance-Diamond Diagnostic Laboratories, University of Exeter, The Innovation Centre, Exeter, UK
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31
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Gupta AK, Kunnumbrath A, Tayal SG, Mehan A, Sahay R, Kumar U, Jeladharan R, Anthony ML, Singh N, Chandra H, Chowdhury N. Short-term biological variation of differential count in healthy subjects in a South Asian population. Scand J Clin Lab Invest 2020; 80:654-658. [PMID: 33016776 DOI: 10.1080/00365513.2020.1827290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Estimates of Within-Subject and between subject biological variation for the white blood cell differential count (DC) have not been reported in South Asia. Therefore, we attempted to measure the short-term biological variation estimates for DC. The study was conducted on 28 healthy volunteers (15 males and 13 females). Blood from the volunteers was collected in the morning in K3-EDTA vials and analyzed in triplicate on the Sysmex XN-1000 analyzer, for six consecutive days. The Within subject, between subject and analytical coefficient of variation of the DC was calculated from the results by nested repeated measures ANOVA after outlier exclusion. The Reference change values (RCV) were also calculated. The within-subject variation for eosinophil Count and between subject variation for basophils in our study from South Asia was greater than the published European and American studies. Males and females showed similar biological variation for DC. The within-subject variation of other parameters (Neutrophils, Lymphocytes, Monocytes and Basophils) were similar or showed only mild differences to the published studies. The markedly different within-subject variation for Eosinophil counts suggest that the RCV for DC in South Asians need to be different from the published data in order to have clinical relevance. The Within-subject variation values of the other parameters seem transportable from the published European and American studies, but the small differences found mean that further regional estimates need to be reported for robust evidence of the same.
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Affiliation(s)
- Arvind Kumar Gupta
- Department of Pathology & Laboratory Medicine, All India Institute of Medical Sciences, Rishikesh, India
| | - Arathi Kunnumbrath
- Department of Pathology & Laboratory Medicine, All India Institute of Medical Sciences, Rishikesh, India
| | - Sakshi Garg Tayal
- Department of Pathology & Laboratory Medicine, All India Institute of Medical Sciences, Rishikesh, India
| | - Anoushika Mehan
- Department of Pathology & Laboratory Medicine, All India Institute of Medical Sciences, Rishikesh, India
| | - Rishabh Sahay
- Department of Pathology & Laboratory Medicine, All India Institute of Medical Sciences, Rishikesh, India
| | - Utpal Kumar
- Department of Pathology & Laboratory Medicine, All India Institute of Medical Sciences, Rishikesh, India
| | - Reshma Jeladharan
- Department of Pathology & Laboratory Medicine, All India Institute of Medical Sciences, Rishikesh, India
| | - Michael Leonard Anthony
- Department of Pathology & Laboratory Medicine, All India Institute of Medical Sciences, Rishikesh, India
| | - Neha Singh
- Department of Pathology & Laboratory Medicine, All India Institute of Medical Sciences, Rishikesh, India
| | - Harish Chandra
- Department of Pathology & Laboratory Medicine, All India Institute of Medical Sciences, Rishikesh, India
| | - Nilotpal Chowdhury
- Department of Pathology & Laboratory Medicine, All India Institute of Medical Sciences, Rishikesh, India
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Li C, Peng M, Wu J, Du Z, Lu H, Zhou W. Long-term biological variation estimates of 13 hematological parameters in healthy Chinese subjects. Clin Chem Lab Med 2020; 58:1282-1290. [PMID: 32069228 DOI: 10.1515/cclm-2019-1141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 12/16/2019] [Indexed: 01/13/2023]
Abstract
Background The complete blood count (CBC) is a basic test routinely ordered by physicians as a part of initial diagnostic work-up on their patients. To ensure safe clinical application of the CBC, reliable biological variation (BV) data are needed to establish analytical performance specifications. Our aim was to define the BV of CBC parameters using a rigorous protocol that is compliant with the Biological Variation Data Critical Appraisal Checklist (BIVAC) provided by the European Federation of Clinical Chemistry and Laboratory Medicine. Methods Blood samples drawn from 41 healthy Chinese subjects (22 females and 19 males; 23-59 years of age) once monthly for 6 consecutive months were analyzed using an ABX Pentra 80 instrument. The instrument was precisely calibrated. All samples were analyzed in duplicate for 13 CBC parameters. The data were assessed for outliers, normality, and variance homogeneity prior to nested ANOVA. Gender-stratified within-subject (CVI) and between-subject (CVG) BV estimates were calculated. Results The number of remaining data for each subject was 442-484 after removing outliers. No significant differences existed between female/male CVI estimates. Except for leukocytes, neutrophils, and lymphocytes, the mean values of 10 parameters differed significantly between genders, rendering partitioning of CVG data between genders. No significant differences were detected between most BV estimates and recently published estimates representing a Europid population. Conclusions Most BV estimates in BIVAC-compliant studies are similar. The turnover time of blood cells and age distribution of participants should be considered in a CBC BV study. Our study will contribute to global BV estimates and future studies.
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Affiliation(s)
- Chenbin Li
- National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Beijing Engineering Research Center of Laboratory Medicine, Beijing, P.R. China.,Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, P.R. China
| | - Mingting Peng
- National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Beijing Engineering Research Center of Laboratory Medicine, Beijing, P.R. China.,Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, P.R. China.,Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P.R. China
| | - Ji Wu
- National Center for Clinical Laboratories, Beijing, P.R. China
| | - Zhongli Du
- National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Beijing Engineering Research Center of Laboratory Medicine, Beijing, P.R. China.,Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, P.R. China
| | - Hong Lu
- National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Beijing Engineering Research Center of Laboratory Medicine, Beijing, P.R. China.,Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, P.R. China
| | - Wenbin Zhou
- National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Beijing Engineering Research Center of Laboratory Medicine, Beijing, P.R. China.,Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, P.R. China
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Ercan M, Akbulut ED, Avcı E, Yücel Ç, Oğuz EF, Turhan T, Serdar M. Determining biological variation of serum parathyroid hormone in healthy adults. Biochem Med (Zagreb) 2019; 29:030702. [PMID: 31379460 PMCID: PMC6610671 DOI: 10.11613/bm.2019.030702] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 05/24/2019] [Indexed: 11/21/2022] Open
Abstract
Introduction Measurement of parathyroid hormone (PTH) is essential in the investigation and management of calcium metabolism disorders. To assess the significance of any assay result when clinical decision making biological variation (BV) of the measurand must be taken into consideration. The aim of the present study is determining the BV parameters for serum PTH. Materials and methods Blood samples were taken at weekly intervals from 20 healthy subjects for ten weeks in this prospective BV study. Serum “intact PTH” concentrations were measured with electrochemiluminescence method. Biological variation parameters were estimated using the approach proposed by Fraser. Results The values of within-subject biological variation (CVI), between-subject biological variation (CVG), analytical variation (CVA), reference change value (RCV) and individuality index (II) for serum PTH were 21.1%, 24.9%, 3.8%, 59.4% and 0.8%, respectively. Within-subject biological variation and CVG were also determined according to gender separately; 18.5% and 24.0%; 26.2% and 18.6% for male and female, respectively. Calculated desirable precision and bias goals were < 10.6% and < 6.3%, respectively. Conclusion This study may contribute to BV data on serum PTH as it includes a sufficient number of volunteers from both genders over an acceptable period of time. We do not recommend the usage of population-based reference intervals for serum PTH concentrations. Reference change value may be helpful for the evaluation of serial serum PTH results. Nonetheless, evaluation of data according to gender is necessary when setting analytical performance specifications.
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Affiliation(s)
- Müjgan Ercan
- Faculty of Medicine, Department of Biochemistry, Harran University, Şanlıurfa, Turkey
| | - Emiş Deniz Akbulut
- Biochemistry Laboratory, University of Health Sciences, Ankara Child Health and Diseases Hematology Oncology Training and Research Hospital, Ankara, Turkey
| | - Esin Avcı
- Faculty of Medicine, Department of Biochemistry, Pamukkale University, Denizli, Turkey
| | - Çiğdem Yücel
- Biochemistry Laboratory, Ankara Numune Training and Research Hospital, Ankara, Turkey
| | - Esra Fırat Oğuz
- Biochemistry Laboratory, Ankara Numune Training and Research Hospital, Ankara, Turkey
| | - Turan Turhan
- Biochemistry Laboratory, Ankara Numune Training and Research Hospital, Ankara, Turkey
| | - Muhittin Serdar
- Faculty of Medicine, Department of Biochemistry, Acıbadem University, İstanbul, Turkey
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Lindberg M, Borgstrøm Hager H, Brokner M. Week-to-week biological variation of methylmalonic acid and homocysteine in healthy women. Scand J Clin Lab Invest 2019; 79:247-250. [PMID: 30957652 DOI: 10.1080/00365513.2019.1590858] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Metylmalonic acid (MMA) and homocysteine (HCY) are important biomarkers in the assessment of cobalamin and folate metabolism. Correct interpretation of patient results benefit from knowledge of biological variation. The aim of the present study was to determine within-subject (CVI) and between-subject (CVG) biological variations of serum MMA and HCY in healthy women. We collected blood samples from 12 healthy volunteers (33-61 years) on the same weekday for 10 consecutive weeks. Samples were stored at -80 °C until analysis in duplicate in a single analytical run in random order. The CVI and CVG biological variations were estimated by CV-ANOVA after the data were first subjected to outlier and homogeneity analysis. The CVI (95% CI) for MMA and HCY were 7.2% (6.1-8.5) and 7.4% (6.5-8.5), respectively. The corresponding CVG were 21.1% (14.0-32.2) and 24.2% (16.2-36.8). The index of individuality (II) was 0.34 for MMA and 0.31 for HCY and the reference change value (RCV) was -17.7; 21.0 (% decrease; increase) for MMA and -16.2; 19.4 for HCY. We provide within- and between-subject biological variation estimates for MMA and HCY in healthy women using an updated protocol. The results will contribute to a better clinical interpretation of these biomarkers and be of aid when setting analytical performance specifications.
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Affiliation(s)
- Morten Lindberg
- a Central Laboratory , Vestfold Hospital Trust , Tønsberg , Norway
| | | | - Mette Brokner
- a Central Laboratory , Vestfold Hospital Trust , Tønsberg , Norway
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Wright ME, Croser EL, Raidal S, Baral RM, Robinson W, Lievaart J, Freeman KP. Biological variation of routine haematology and biochemistry measurands in the horse. Equine Vet J 2018; 51:384-390. [PMID: 30194868 DOI: 10.1111/evj.13017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 09/06/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND Clinical pathology results are typically interpreted by referring to population-based reference intervals. The use of individualised (subject-based) reference intervals is more appropriate for measurands with a high degree of variation between individuals. OBJECTIVES To determine the biological variation of routinely analysed equine haematology and biochemistry measurands and calculate indices of individuality and reference change values which enable production of individualised reference intervals, in a group of healthy, privately owned horses. STUDY DESIGN In a prospective cohort study, thirty-nine privately owned horses were sampled by jugular venipuncture for analysis of haematology and biochemistry measurands at weekly intervals for 6 weeks. METHODS Haematology was analysed on the day of collection. Serum was frozen and biochemistry analyses performed on thawed samples. Duplicate results were obtained and the coefficient of variation was calculated for analytical variation, within-subject variation and between-subject variation. The index of individuality and reference change value were derived for each measurand. RESULTS Haematology (red blood cell count, mean corpuscular haemoglobin and mean cell volume) and biochemistry measurands (total protein, globulins, albumin, gamma-glutamyl transferase, aspartate aminotransferase) demonstrated high individuality, indicating that individualised reference intervals are more appropriate for evaluation of these measurands. Two haematology (mean corpuscular haemoglobin concentration and platelets) and three biochemistry measurands (chloride, glucose and sodium) had low individuality, indicating that the use of traditional population-based reference intervals is appropriate for these measurands. Remaining measurands had intermediate individuality suggesting interpretation of the reference change value should occur with consideration of the population-based reference interval. MAIN LIMITATIONS The use of privately owned horses, variable management and environmental factors. CONCLUSIONS The use of individualised reference intervals is justified for many measurands in horses, supporting the use of serial sampling, consideration of biological variation and application of reference change values for improved clinical decision making and patient management in equine practice.
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Affiliation(s)
- M E Wright
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - E L Croser
- Veterinary Diagnostic Laboratory, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - S Raidal
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - R M Baral
- Paddington Cat Hospital, Paddington, New South Wales, Australia
| | - W Robinson
- Quantitative Consulting Unit, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - J Lievaart
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
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Fernández-Grande E, Valera-Rodriguez C, Sáenz-Mateos L, Sastre-Gómez A, García-Chico P, Palomino-Muñoz TJ. Impact of reference change value (RCV) based autoverification on turnaround time and physician satisfaction. Biochem Med (Zagreb) 2017; 27:342-349. [PMID: 28694725 PMCID: PMC5493162 DOI: 10.11613/bm.2017.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 04/30/2017] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND For a quicker delivery of laboratory test results to the hospital emergency department (ED), we implemented an autoverification system based on the reference change value (RCV). The aim of this study was to assess how the RCV based autoverification reflected on turnaround time (TAT) and on physician satisfaction. MATERIALS AND METHODS The laboratory information system (LIS) was programmed to autoverify the results as long as they were within the range settled by RCV, so that the autoverified results were reported to the physician as soon as the tests were carried out, without any further intervention. We analyzed the same three-month periods' TAT and verification time (VFT) from the years prior to and following the implementation of RCV autoverification. The change in physicians' satisfaction levels was assessed using the hospital's Annual Physician Satisfaction Survey (APSS). Over sixty percent of physicians completed the questionnaire, and the amount of daily ED test requests (nearly three hundred) did not vary throughout the duration of this study. RESULTS Mann-Whitney U test showed that the VFT was significantly reduced in all the test but troponin I. There were substantial reductions in TAT medians (haemogram, 75%; fibrinogen, 41%; prothrombin time, 40%; sodium, 27%). The percentage of physicians satisfied with the haematological and biochemical tests´ TAT increased from 84% to 93% and from 86% to 91% respectively. CONCLUSIONS Our results reveal that VFT and TAT were severely reduced in most emergency tests, greatly improving physicians' satisfaction with TAT.
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Affiliation(s)
- Esther Fernández-Grande
- Servicio de Análisis Clínicos, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain
| | | | - Luis Sáenz-Mateos
- Servicio de Análisis Clínicos, Complejo Hospitalario de Navarra, Pamplona, Spain
| | - Amparo Sastre-Gómez
- Servicio de Análisis Clínicos, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain
| | - Pilar García-Chico
- Servicio de Análisis Clínicos, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain
| | - Teodoro J Palomino-Muñoz
- Servicio de Análisis Clínicos, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain
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Hilderink JM, Klinkenberg LJJ, Aakre KM, de Wit NCJ, Henskens YMC, van der Linden N, Bekers O, Rennenberg RJMW, Koopmans RP, Meex SJR. Within-day biological variation and hour-to-hour reference change values for hematological parameters. Clin Chem Lab Med 2017; 55:1013-1024. [PMID: 28002028 DOI: 10.1515/cclm-2016-0716] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 11/01/2016] [Indexed: 01/24/2023]
Abstract
BACKGROUND Middle- and long-term biological variation data for hematological parameters have been reported in the literature. Within-day 24-h variability profiles for hematological parameters are currently lacking. However, comprehensive hour-to-hour variability data are critical to detect diurnal cyclical rhythms, and to take into account the 'time of sample collection' as a possible determinant of natural fluctuation. In this study, we assessed 24-h variation profiles for 20 hematological parameters. METHODS Blood samples were collected under standardized conditions from 24 subjects every hour for 24 h. At each measurement, 20 hematological parameters were determined in duplicate. Analytical variation (CVA), within-subject biological variation (CVI), between-subject biological variation (CVG), index of individuality (II), and reference change values (RCVs) were calculated. For the parameters with a diurnal rhythm, hour-to-hour RCVs were determined. RESULTS All parameters showed higher CVG than CVI. Highest CVG was found for eosinophils (46.6%; 95% CI, 34.9%-70.1%) and the lowest value was mean corpuscular hemoglobin concentration (MCHC) (3.2%; 95% CI, 2.4%-4.8%). CVI varied from 0.4% (95% CI, 0.32%-0.42%) to 20.9% (95% CI, 19.4%-22.6%) for red cell distribution width (RDW) and eosinophils, respectively. Six hematological parameters showed a diurnal rhythm. CONCLUSIONS We present complete 24-h variability profiles for 20 hematological parameters. Hour-to-hour reference changes values may help to better discriminate between random fluctuations and true changes in parameters with rhythmic diurnal oscillations.
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Lund F, Petersen PH, Fraser CG, Sölétormos G. Different percentages of false-positive results obtained using five methods for the calculation of reference change values based on simulated normal and ln-normal distributions of data. Ann Clin Biochem 2016; 53:692-698. [PMID: 27151961 DOI: 10.1177/0004563216643729] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Reference change values provide objective tools to assess the significance of a change in two consecutive results for a biomarker from an individual. The reference change value calculation is based on the assumption that within-subject biological variation has random fluctuation around a homeostatic set point that follows a normal (Gaussian) distribution. This set point (or baseline in steady-state) should be estimated from a set of previous samples, but, in practice, decisions based on reference change value are often based on only two consecutive results. The original reference change value was based on standard deviations according to the assumption of normality, but was soon changed to coefficients of variation (CV) in the formula (reference change value = ± Z ċ 2½ ċ CV). Z is being dependent on the desired probability of significance, which also defines the percentages of false-positive results. The aim of this study was to investigate false-positive results using five different published methods for calculation of reference change value. Methods The five reference change value methods were examined using normally and ln-normally distributed simulated data. Results One method performed best in approaching the theoretical false-positive percentages on normally distributed data and another method performed best on ln-normally distributed data. The commonly used reference change value method based on two results (without use of estimated set point) performed worst both on normally distributed and ln-normally distributed data. Conclusions The optimal choice of method to calculate reference change value limits requires knowledge of the distribution of data (normal or ln-normal) and, if possible, knowledge of the homeostatic set point.
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Affiliation(s)
- Flemming Lund
- 1 Department of Clinical Biochemistry, North Zealand Hospital, University of Copenhagen, Hillerød, Denmark
| | - Per Hyltoft Petersen
- 1 Department of Clinical Biochemistry, North Zealand Hospital, University of Copenhagen, Hillerød, Denmark.,2 Norwegian Quality Improvement of Primary Care Laboratories (NOKLUS), Section for General Practice, University of Bergen, Bergen, Norway
| | - Callum G Fraser
- 3 Centre for Research into Cancer Prevention and Screening, University of Dundee, Dundee, Scotland
| | - György Sölétormos
- 1 Department of Clinical Biochemistry, North Zealand Hospital, University of Copenhagen, Hillerød, Denmark
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Falkenö U, Hillström A, von Brömssen C, Strage EM. Biological variation of 20 analytes measured in serum from clinically healthy domestic cats. J Vet Diagn Invest 2016; 28:699-704. [PMID: 27638843 DOI: 10.1177/1040638716666602] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The applications of data on biological variation include assessment of the utility of population-based reference intervals, evaluation of the significance of change in serial results, and setting of analytical quality specifications. We investigated the biological variation of 19 biochemistry analytes and total T4, measured in serum from 7 clinically healthy domestic cats sampled once weekly for 5 weeks. Samples were frozen and analyzed in random order in the same analytical run. Results were analyzed for outliers, and the components of variance, subsequently generated by restricted maximum likelihood, were used to determine within-subject and between-subject variation (CVI and CVG, respectively), as well as analytical variation (CVA) for each analyte. Indices of individuality, reference change values, and analytical performance goals were calculated. The smallest CVI and CVG were found for calcium, chloride, and sodium, whereas the largest values were calculated for bile acids. Nine analytes (albumin, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, cholesterol, creatinine, phosphate [phosphorus], total protein, total T4) demonstrated high individuality, indicating limited utility of population-based reference intervals. Individuality was low, and population-based reference intervals were thereby considered appropriate for 5 analytes (bile acids, calcium, fructosamine, glucose, potassium). The intermediate individuality observed for 4 analytes (creatine kinase, iron, magnesium, urea) indicated that population-based reference intervals should be used with caution.
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Affiliation(s)
- Ulrika Falkenö
- Clinical Pathology Laboratory, University Animal Hospital (Falkenö, Hillström, Strage), Swedish University of Agricultural Sciences, Uppsala, SwedenDepartment of Clinical Sciences, Faculty of Veterinary Medicine and Animal Sciences (Strage), Swedish University of Agricultural Sciences, Uppsala, SwedenDepartment of Economics (von Brömssen), Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anna Hillström
- Clinical Pathology Laboratory, University Animal Hospital (Falkenö, Hillström, Strage), Swedish University of Agricultural Sciences, Uppsala, SwedenDepartment of Clinical Sciences, Faculty of Veterinary Medicine and Animal Sciences (Strage), Swedish University of Agricultural Sciences, Uppsala, SwedenDepartment of Economics (von Brömssen), Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Claudia von Brömssen
- Clinical Pathology Laboratory, University Animal Hospital (Falkenö, Hillström, Strage), Swedish University of Agricultural Sciences, Uppsala, SwedenDepartment of Clinical Sciences, Faculty of Veterinary Medicine and Animal Sciences (Strage), Swedish University of Agricultural Sciences, Uppsala, SwedenDepartment of Economics (von Brömssen), Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Emma M Strage
- Clinical Pathology Laboratory, University Animal Hospital (Falkenö, Hillström, Strage), Swedish University of Agricultural Sciences, Uppsala, SwedenDepartment of Clinical Sciences, Faculty of Veterinary Medicine and Animal Sciences (Strage), Swedish University of Agricultural Sciences, Uppsala, SwedenDepartment of Economics (von Brömssen), Swedish University of Agricultural Sciences, Uppsala, Sweden
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Matyar S, Goruroglu Ozturk O, Ziyanoglu Karacor E, Yuzbasioglu Ariyurek S, Sahin G, Kibar F, Yaman A, Inal T. Biological Variation and Reference Change Value Data for Serum Neuron-Specific Enolase in a Turkish Population. J Clin Lab Anal 2016; 30:1081-1085. [PMID: 27121140 DOI: 10.1002/jcla.21984] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 03/30/2016] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Neuron-specific enolase (NSE) is a recognized biomarker for the assessment of cerebral injury in neurological disorders. This study aims to report a definitive assessment of the biological variation (BV) components of this biomarker, including within-subject BV (CVI), between-subject BV (CVG), index of individuality (II), and reference change value (RCV), in a cohort of Turkish participants using an experimental protocol. METHODS Six blood specimens were collected from each of the 13 apparently healthy volunteers (seven women, six men; ranging in age from 23 to 36) on the same day, every 2 weeks for 2 months. Serum specimens were stored at -20°C until analysis. Neuron-specific enolase levels were evaluated in serum samples using an electrochemiluminescence (ECLIA) immunoassay kit with a Roche Cobas e 411 auto-analyser. ANOVA test was used to calculate the variations. RESULTS The CVI and CVG for NSE were 21.5% and 28.8%, respectively. Analytical variation (CVA) was calculated as 10.2%. Additionally, II and RCV were calculated as 0.74 and 66% (95% confident interval, CI), respectively. CONCLUSION As the performance index (PI) was found to be less than 2 (PI = 0.95), it is concluded that the NSE measurements have a desirable performance for analytical imprecision. Since the II was found to be less than 1 (II: 0.74), the reference values will be of little use. Thus, RCV would provide better information for deciding whether a significant change has occurred.
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Affiliation(s)
- Selcuk Matyar
- Central Laboratory, Medical Faculty, Balcali Hospital, Cukurova University, Adana, Turkey.
| | - Ozlem Goruroglu Ozturk
- Department of Clinical Biochemistry, Medical Faculty, Cukurova University, Adana, Turkey
| | - Esin Ziyanoglu Karacor
- Department of Clinical Biochemistry, Medical Faculty, Cukurova University, Adana, Turkey
| | | | - Gulhan Sahin
- Department of Clinical Biochemistry, Medical Faculty, Cukurova University, Adana, Turkey
| | - Filiz Kibar
- Department of Clinical Microbiology, Medical Faculty, Cukurova University, Adana, Turkey
| | - Akgun Yaman
- Department of Clinical Microbiology, Medical Faculty, Cukurova University, Adana, Turkey
| | - Tamer Inal
- Department of Clinical Biochemistry, Medical Faculty, Cukurova University, Adana, Turkey
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Demir S, Zorbozan N, Basak E. Unnecessary repeated total cholesterol tests in biochemistry laboratory. Biochem Med (Zagreb) 2016; 26:77-81. [PMID: 26981021 PMCID: PMC4783093 DOI: 10.11613/bm.2016.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/31/2015] [Indexed: 11/15/2022] Open
Abstract
INTRODUCTION We aimed to determine the number of repeated cholesterol (RC) tests and the ratio of unnecessary-repeated cholesterol (URC) tests among patients admitted to Pamukkale University Hospital (Denizli, Turkey) and provide solutions to avoid URC testing. MATERIALS AND METHODS Total cholesterol (T-cholesterol) tests (N = 86,817) between June 2014 and May 2015 were evaluated. The tests performed more than once per patient were determined as RC test (N = 28,811). RC test with an interval shorter than 4 weeks were determined as URC test (N = 3968) according to the shortest retest interval stated in ACC/AHA blood cholesterol guideline. RC testing included internal medicine, surgery and paediatric outpatients and inpatients. Reference change value (RCV) of total cholesterol was calculated. RESULTS The 33.1% of the T-cholesterol tests were RC tests (N = 28,811), 13.7% of them were URC tests (N = 3968). Our RCV value was 25%. The percentage change between consecutive tests was less than RCV in 86.1% (N = 3418) of URC tests. URC tests were performed more frequently in patients with desirable total cholesterol value (P < 0.001). CONCLUSION There is a significant part of repeated T-cholesterol tests requested in our hospital. URC test requests can be evaluated by laboratories and the obtained data should be shared with clinicians. Laboratories can calculate RCV for the tests they performed and report this value with the test result. To prevent from URC tests, a warning plug-in can be added to hospital information software in accordance with guidelines to prevent from URC test requests.
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Affiliation(s)
- Suleyman Demir
- Pamukkale University, Faculty of Medicine, Department of Medical Biochemistry, Denizli, Turkey
| | - Nergiz Zorbozan
- Pamukkale University, Faculty of Medicine, Department of Medical Biochemistry, Denizli, Turkey
| | - Elif Basak
- Pamukkale University, Faculty of Medicine, Department of Medical Biochemistry, Denizli, Turkey
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Scruggs JL, Flatland B, McCormick KA, Reed A. Biological variation of thromboelastrography variables in 10 clinically healthy horses. J Vet Emerg Crit Care (San Antonio) 2015; 26:80-4. [PMID: 26479874 DOI: 10.1111/vec.12410] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 01/21/2014] [Accepted: 09/04/2015] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To assess the utility of population-based reference intervals (PRIs) for interpreting thromboelastography (TEG) variables in horses using biological variation data. DESIGN Prospective cohort biologic variation study conducted over a 5-week period. SETTING Veterinary teaching hospital and research facility. ANIMALS Ten clinically healthy horses randomly selected from a veterinary school research and teaching herd. INTERVENTIONS Horse health was determined using physical examination, CBC, and biochemical and coagulation profiles prior to the start of the study. Subsequently, once weekly blood sampling for TEG testing was performed for 5 weeks. MEASUREMENTS AND MAIN RESULTS The 4 TEG variables reaction time (R), clot formation time (K), angle, and maximum amplitude (MA) were measured, and coefficient of variation representing within- and between-horse biological variation (CVi and CVg , respectively) and coefficient of variation representing analytical variation (CVa ) were calculated using a nested ANOVA after removing outlier data. The CVi , CVg , and CVa for R were 26.8%, 5.2%, and 5.9%; for K were 31.0%, 0.0%, and 5.9%; for angle were 9.4%, 6.2%, and 21.7%; and for MA were 3.4%, 4.1%, and 4.4%, respectively. Index of individuality (IOI) was then calculated for each variable using the formula {( CVi² + CVa²/CVg²)}¹/². IOI for R was 5.3, for angle was 3.8, and for MA was 1.4; IOI was not assessed for K. CONCLUSIONS PRIs are appropriate for TEG variables, R, angle, and MA when interpreting results from individual horses based on calculated IOI values equal to or greater than 1.4. PRIs are likely appropriate when interpreting K, but IOI could not be calculated for this variable.
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Affiliation(s)
- Jennifer L Scruggs
- Departments of Biomedical and Diagnostic Sciences, University of Tennessee, Knoxville, TN, 37996
| | - Bente Flatland
- Departments of Biomedical and Diagnostic Sciences, University of Tennessee, Knoxville, TN, 37996
| | - Karen A McCormick
- Large Animal Clinical Sciences, University of Tennessee, Knoxville, TN, 37996
| | - Ann Reed
- College of Veterinary Medicine and the Office of Information Technology, University of Tennessee, Knoxville, TN, 37996
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Hickman PE, Lindahl B, Cullen L, Koerbin G, Tate J, Potter JM. Decision limits and the reporting of cardiac troponin: Meeting the needs of both the cardiologist and the ED physician. Crit Rev Clin Lab Sci 2014; 52:28-44. [PMID: 25397345 DOI: 10.3109/10408363.2014.972497] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Cardiac troponin is the preferred biomarker for defining the acute coronary syndrome and acute myocardial infarction. Currently, the only decision limit formally endorsed with regard to the cardiac troponins is the 99th percentile. This is a "rule-in" criterion, intended to ensure that only persons with the acute coronary syndrome are reviewed. The 99th percentile is an arbitrary cut point and there are many problems associated with its application, including defining a truly healthy population, the difficulty of standardisation of cardiac troponin assays, especially but not only cardiac troponin I, and the effects of age and sex on this parameter. The Emergency Department (ED) screens many more persons for possible acute coronary syndromes than actually have the condition and their needs are best met by a "rule-out" test that enables them to clear their busy departments of the many persons who do not actually have the condition. The needs of the ED are not optimally met using the 99th percentile. The index of individuality for the cardiac troponins is small and significant changes consistent with an acute coronary syndrome can occur without the 99th percentile being exceeded. It appears that the ED may be better served by use of delta troponin changes rather than the 99th percentile, but there are problems with this approach, particularly in persons who present late when troponin release has plateaued. In addition, there are many non-acute coronary syndrome causes for cardiac troponin release. The needs of the cardiologist and the ED physician are so different that it may be inappropriate for both groups to use the same diagnostic criteria for cardiac troponin, and it is of great importance that cardiac troponin measurement be used as only one part of the assessment of the person presenting with possible acute coronary syndrome.
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McEntyre CJ, Lever M, Chambers ST, George PM, Slow S, Elmslie JL, Florkowski CM, Lunt H, Krebs JD. Variation of betaine, N,N-dimethylglycine, choline, glycerophosphorylcholine, taurine and trimethylamine-N-oxide in the plasma and urine of overweight people with type 2 diabetes over a two-year period. Ann Clin Biochem 2014; 52:352-60. [PMID: 25013088 DOI: 10.1177/0004563214545346] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2014] [Indexed: 02/06/2023]
Abstract
BACKGROUND Plasma betaine concentrations and urinary betaine excretions have high test-retest reliability. Abnormal betaine excretion is common in diabetes. We aimed to confirm the individuality of plasma betaine and urinary betaine excretion in an overweight population with type 2 diabetes and compare this with the individuality of other osmolytes, one-carbon metabolites and trimethylamine-N-oxide (TMAO), thus assessing their potential usefulness as disease markers. METHODS Urine and plasma were collected from overweight subjects with type 2 diabetes at four time points over a two-year period. We measured the concentrations of the osmolytes: betaine, glycerophosphorylcholine (GPC) and taurine, as well as TMAO, and the one-carbon metabolites, N,N-dimethylglycine (DMG) and free choline. Samples were measured using tandem mass spectrometry (LC-MS/MS). RESULTS Betaine showed a high degree of individuality (or test-retest reliability) in the plasma (index of individuality = 0.52) and urine (index of individuality = 0.45). Betaine in the plasma had positive and negative log-normal reference change values (RCVs) of 54% and -35%, respectively. The other osmolytes, taurine and GPC were more variable in the plasma of individuals compared to the urine. DMG and choline showed high individuality in the plasma and urine. TMAO was highly variable in the plasma and urine (log-normal RCVs ranging from 403% to -80% in plasma). CONCLUSIONS Betaine is highly individual in overweight people with diabetes. Betaine, its metabolite DMG, and precursor choline showed more reliability than the osmolytes, GPC and taurine. The low reliability of TMAO suggests that a single TMAO measurement has low diagnostic value.
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Affiliation(s)
- Christopher J McEntyre
- Biochemistry Unit, Canterbury Health Laboratories, Christchurch, New Zealand Department of Chemistry, University of Canterbury, Christchurch, New Zealand
| | - Michael Lever
- Biochemistry Unit, Canterbury Health Laboratories, Christchurch, New Zealand Department of Chemistry, University of Canterbury, Christchurch, New Zealand
| | - Stephen T Chambers
- Department of Pathology, University of Otago, Christchurch; Christchurch, New Zealand
| | - Peter M George
- Biochemistry Unit, Canterbury Health Laboratories, Christchurch, New Zealand Department of Pathology, University of Otago, Christchurch; Christchurch, New Zealand
| | - Sandy Slow
- Department of Pathology, University of Otago, Christchurch; Christchurch, New Zealand
| | - Jane L Elmslie
- Biochemistry Unit, Canterbury Health Laboratories, Christchurch, New Zealand
| | | | - Helen Lunt
- Department of Medicine, University of Otago, Christchurch; Christchurch, New Zealand
| | - Jeremy D Krebs
- Department of Medicine, University of Otago, Wellington; Wellington, New Zealand
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Ozturk OG, Paydas S, Balal M, Sahin G, Karacor EDZ, Ariyurek SY, Yaman A. Biological variations of some analytes in renal posttransplant patients: a different way to assess routine parameters. J Clin Lab Anal 2014; 27:438-43. [PMID: 24218125 DOI: 10.1002/jcla.21625] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 04/11/2013] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Biological variation (BV) data of analytes have been used to evaluate the significant changes in serial results (reference change value, RCV) of healthy individuals in clinical laboratories. However, BV data of healthy subjects may not be identical to the analytes of patients with ongoing clinical condition. The aim of this study was to calculate intra-(CVw) (coefficient of variation for intra-individual BV) and inter-individual (CVg) BV, index of individuality, and RCV of nine serum analytes of renal posttransplant patients. METHODS Six serum specimens were obtained in an interval of two months in a one-year period from 70 transplant patients who had been stable for three years. Each time creatinine, uric acid, urea, sodium, potassium, calcium, inorganic phosphate, total protein, and albumin of these patients were analyzed with an integrated clinical chemistry/immunoassay auto-analyzer. ANOVA tests were used to calculate the variations. Results were compared with the data of healthy subjects obtained from BV database. RESULTS CVw of all nine analytes of the renal transplant patients were higher than the healthy subjects. RCVs of these analytes were calculated as 14.5% for creatinine, 16.5% for urea, 13.7% for urate, 12.57% for albumin, 8.26% for total protein, 3.25% for sodium, 12.81% for potassium, 5.88% for calcium, and 21.57% for inorganic phosphate. CONCLUSION RCV concept for predicting the clinical status in posttransplant population represents an optimization of laboratory reporting and could be a valuable tool for clinical decision.
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Affiliation(s)
- Ozlem Goruroglu Ozturk
- Department of Clinical Biochemistry, Faculty of Medicine, Cukurova University, Adana, Turkey; Cukurova University, Balcali Hospital, Central Laboratory, Adana, Turkey
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Abstract
The National Institute for Health and Clinical Excellence (NICE) guidelines have sparked hot debate regarding the role of carbohydrate antigen 125 (CA-125) for ovarian cancer (OC) detection. Recent literature and evidence calls into question the use of CA-125 in diagnostic algorithms, given the better performance of human epididymis protein 4 (HE4) vs. CA-125 to rule OC. This is an important consideration since combined measurements are not cost-effective. The quality of this evidence is, however, threatened by important gaps related to study design, enrolled populations and analytical issues. For instance, despite the clinical need to prioritize the evaluation of biomarker performance in early stage tumours, sound evidence on this cannot be provided. In addition, results should be cautiously interpreted due to wide differences in the type of employed assays and in adopted diagnostic thresholds for HE4. Comparability among results obtained by different commercially available HE4 assays, together with an objective establishment of analytical goals is essential for the optimal clinical application of this marker.
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Affiliation(s)
- Simona Ferraro
- Cattedra di Biochimica Clinica e Biologia Molecolare Clinica, Dipartimento di Scienze Biomediche e Cliniche "Luigi Sacco", Università degli Studi, Milano, Italy
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Dieplinger B, Egger M, Gabriel C, Poelz W, Morandell E, Seeber B, Kronenberg F, Haltmayer M, Mueller T, Dieplinger H. Analytical characterization and clinical evaluation of an enzyme-linked immunosorbent assay for measurement of afamin in human plasma. Clin Chim Acta 2013; 425:236-41. [PMID: 23981841 PMCID: PMC3819992 DOI: 10.1016/j.cca.2013.08.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 08/16/2013] [Accepted: 08/16/2013] [Indexed: 11/09/2022]
Abstract
Background Comparative proteomics has recently identified afamin, the newest member of the albumin gene family, as a potential biomarker for ovarian cancer. The aim of this study was the analytical and clinical evaluation of a sandwich enzyme-linked immunosorbent assay for the determination of afamin in human plasma. Methods We evaluated precision, linearity, and detection limit of the assay, analyte stability and biological variability, determined reference values and quantified afamin concentrations in various diseases. Results Within-run and total coefficients of variation were < 10%. The method was linear across the tested measurement range. Detection limit was 7 mg/L for the assay. The analyte was stable for 24 h at room temperature, for 48 h at 4 °C, and for at least one year at − 20 °C and − 80 °C. The reference change value for healthy individuals was 24%. Age- and sex-independent reference values in healthy blood donors were 45–99 mg/L (median 68 mg/L). In the clinical assay evaluation afamin plasma concentrations were modestly decreased in patients with heart failure. Patients with pneumonia or sepsis exhibited markedly decreased afamin plasma concentrations. However, patients with chronic renal disease or chronic obstructive pulmonary disease showed no difference in afamin plasma concentrations as compared to healthy individuals. Correlation analyses revealed an inverse association between afamin and inflammatory biomarkers. Conclusions The afamin assay meets quality specifications for laboratory medicine. The results of the clinical assay evaluation revealed novel insights with respect to afamin as a potential negative acute phase protein and should encourage further studies. The aim of this study was the analytical and clinical evaluation of a human afamin ELISA. The afamin assay meets the needs of quality specifications of laboratory medicine. Afamin exerts a good in vitro stability which is important of preanalytical issues. The RCV was 24% and reference values in healthy blood donors were 45–99 mg/L. We revealed novel insights with respect to afamin as a potential negative acute phase protein.
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Affiliation(s)
- Benjamin Dieplinger
- Department of Laboratory Medicine, Konventhospital Barmherzige Brueder Linz, Linz, Austria.
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