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Delanghe J, Oyaert M, De Buyzere M, Delanghe S, Speeckaert M. Glucosuria and interference of urinary albumin-to-creatinine ratio. Kidney Int 2023; 104:201. [PMID: 37349050 DOI: 10.1016/j.kint.2023.03.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 03/24/2023] [Indexed: 06/24/2023]
Affiliation(s)
- Joris Delanghe
- Department of Laboratory Medicine, Ghent University Hospital, Ghent, Belgium.
| | - Matthijs Oyaert
- Department of Laboratory Medicine, Ghent University Hospital, Ghent, Belgium
| | - Marc De Buyzere
- Department of Internal Medicine, Ghent University Hospital, Ghent, Belgium
| | - Sigurd Delanghe
- Department of Nephrology, Ghent University Hospital, Ghent, Belgium
| | - Marijn Speeckaert
- Department of Nephrology, Ghent University Hospital, Ghent, Belgium; Research Foundation Flanders, Brussels, Belgium
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2
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Nataatmadja M, Fung AWS, Jacobson B, Ferera J, Bernstein E, Komenda P, Mattman A, Seccombe D, Levin A. Performance of StatSensor Point-of-Care Device for Measuring Creatinine in Patients With Chronic Kidney Disease and Postkidney Transplantation. Can J Kidney Health Dis 2020; 7:2054358120970716. [PMID: 33240520 PMCID: PMC7672720 DOI: 10.1177/2054358120970716] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 09/25/2020] [Indexed: 11/28/2022] Open
Abstract
Background: The StatSensor is a point-of-care device which measures creatinine in capillary whole blood. Previous studies reported an underestimation of the creatinine measurements at high creatinine concentrations and were performed in the prestandardization era for creatinine. Objective: This accuracy-based study evaluates the use of this device in kidney-transplanted patients and those with chronic kidney disease (CKD). Design: Cross-sectional diagnostic accuracy study. Setting: Nephrology outpatient clinic in an urban tertiary center. Participants: Adults with CKD or a functioning kidney transplant. Measurements: Duplicate StatSensor creatinine measurements were performed on capillary whole blood samples collected by direct fingerstick and SAFE-T-FILL collection device. Results were compared with simultaneous venous blood sampling for serum and plasma creatinine measured by an enzymatic method on the Roche Integra 400 mainframe analyzer with traceability to the ID-GC-MS (isotope dilution gas chromatography mass spectrometry) reference method. Methods: Deming regression, Pearson correlation coefficient, and Bland-Altman analysis were used to assess accuracy and comparability between capillary whole blood measured by StatSensor and plasma creatinine measured by routine analyzer with traceability to the reference method. Estimated glomerular filtration (eGFR) rates were calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and concordance with Kidney Disease Improving Global Outcomes (KDIGO) CKD stage classification was evaluated. Results: There were 60 participants (mean age = 61.9 ± 15.0 years, 55% men, 33% transplant, mean plasma creatinine = 137 ± 59 µmol/L). Bland-Altman analysis indicated a positive mean bias of 12.7 µmol/L between StatSensor fingerstick creatinine measurement and plasma creatinine. Comparison of eGFR (CKD-EPI) calculated from the StatSensor fingerstick creatinine versus plasma creatinine showed misclassification across all KDIGO CKD stages. Postanalytical correction of the bias did not improve misclassifications. The use of mean of duplicate StatSensor creatinine results did not improve performance compared with the use of singlet results. Limitations: Single center, limited participant numbers. Conclusions: The results of our study suggest that the limiting characteristics of the StatSensor device are not only bias, but also imprecision. The level of imprecision observed may influence clinical decision-making and limit the usefulness of StatSensor as a CKD screening tool. If choosing to utilize it for either screening for or monitoring CKD, it is essential that clinicians understand the limitations of point-of-care devices and apply this knowledge to test interpretation.
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Affiliation(s)
- Melissa Nataatmadja
- Sunshine Coast Hospital and Health Service, Birtinya, Queensland, Australia.,Faculty of Medicine, The University of Queensland, Brisbane, Australia.,Division of Nephrology, The University of British Columbia, Vancouver, Canada
| | - Angela W S Fung
- Department of Pathology and Laboratory Medicine, St. Paul's Hospital, Vancouver, BC, Canada
| | | | - Jack Ferera
- BC Provincial Renal Agency, Vancouver, Canada
| | | | - Paul Komenda
- Max Rady Department of Medicine, Section of Nephrology, University of Manitoba, Winnipeg, Canada.,Chronic Disease Innovation Centre, Winnipeg, MB, Canada
| | - Andre Mattman
- Department of Pathology and Laboratory Medicine, St. Paul's Hospital, Vancouver, BC, Canada
| | | | - Adeera Levin
- Division of Nephrology, The University of British Columbia, Vancouver, Canada.,BC Provincial Renal Agency, Vancouver, Canada.,Division of Nephrology, St. Paul's Hospital, Vancouver, BC, Canada
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Paediatric Reference Intervals: Current Status, Gaps, Challenges and Future Considerations. Clin Biochem Rev 2020; 41:43-52. [PMID: 32518426 DOI: 10.33176/aacb-19-00036] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Establishing paediatric reference intervals (RIs) is a challenging task due to difficulties in subject recruitment, collection of adequate blood volume, and the inherent physiological changes of many biomarkers with age. Despite these challenges, several national and international initiatives have demonstrated: (a) the feasibility of prospectively designed paediatric RI studies; (b) the development of continuous RIs; and (c) the comparison of reference values across analyser types to harmonise paediatric RIs. Whilst these studies have improved the interpretation of paediatric test results and compliance with international accreditation (ISO15189) requirements, several gaps and challenges in translating current paediatric RIs into routine laboratory practice remain. Future priorities for paediatric RI studies include: (a) determination of the impact of discrete versus continuous RIs, analyser-specific versus harmonised RIs, and prospective collection versus data mining on the proportion of results outside the RIs; (b) understanding the clinical implications of analyser-to-analyser variation in reference values and use of evidence-based paediatric harmonised RIs where applicable; (c) adaptation of laboratory information systems to incorporate continuous RIs; (d) further understanding of the biological variation in paediatric biomarkers; (e) studies to address the paucity of accurate data for neonatal RI development; (f) periodic demonstration of RIs being clinically 'fit-for purpose'; and (g) agreement and policy updates for use of modern, best practice statistical methods in estimation of paediatric RIs. Furthermore, in vitro diagnostic manufacturers may require incentivised paediatric RI studies and publications through co-ordinated grants and collaboration at end-user sites to reduce the burden on sole users.
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Hoq M, Matthews S, Karlaftis V, Burgess J, Cowley J, Donath S, Carlin J, Yen T, Ignjatovic V, Monagle P. Reference Values for 30 Common Biochemistry Analytes Across 5 Different Analyzers in Neonates and Children 30 Days to 18 Years of Age. Clin Chem 2019; 65:1317-1326. [DOI: 10.1373/clinchem.2019.306431] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/01/2019] [Indexed: 01/04/2023]
Abstract
AbstractBACKGROUNDAge-specific reference intervals (RIs) have been developed for biochemistry analytes in children. However, the ability to interpret results from multiple laboratories for 1 individual is limited. This study reports a head-to-head comparison of reference values and age-specific RIs for 30 biochemistry analytes for children across 5 analyzer types.METHODSBlood was collected from healthy newborns and children 30 days to <18 years of age. Serum aliquots from the same individual were analyzed on 5 analyzer types. Differences in the mean reference values of the analytes by the analyzer types were investigated using mixed-effect regression analysis and by comparing maximum variation between analyzers with analyte-specific allowable total error reported in the Westgard QC database. Quantile regression was used to estimate age-specific RIs using power variables in age selected by fractional polynomial regression for the mean, with modification by sex when appropriate.RESULTSThe variations of age-specific mean reference values between analyzer types were within allowable total error (Westgard QC) for most analytes, and common age-specific reference limits were reported as functions of age and/or sex. Analyzer-specific reference limits for all analytes on 5 analyzer types are also reported as functions of age and/or sex.CONCLUSIONSThis study provides quantitative and qualitative measures of the extent to which results for individual children can or cannot be compared across analyzer types, and the feasibility of RI harmonization. The reported equations enable incorporation of age-specific RIs into laboratory information systems for improving evidence-based clinical decisions in children.
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Affiliation(s)
- Monsurul Hoq
- Murdoch Children's Research Institute, Parkville, Australia
- The University of Melbourne, Parkville, Australia
| | - Susan Matthews
- The Royal Children's Hospital, Parkville, Australia
- International Centre for Point of Care Testing, Flinders University, Bedford Park, Australia
| | | | | | - Jessica Cowley
- Murdoch Children's Research Institute, Parkville, Australia
- The Royal Children's Hospital, Parkville, Australia
| | - Susan Donath
- Murdoch Children's Research Institute, Parkville, Australia
- The University of Melbourne, Parkville, Australia
| | - John Carlin
- Murdoch Children's Research Institute, Parkville, Australia
- The University of Melbourne, Parkville, Australia
| | - Tina Yen
- The Royal Children's Hospital, Parkville, Australia
| | - Vera Ignjatovic
- Murdoch Children's Research Institute, Parkville, Australia
- The University of Melbourne, Parkville, Australia
| | - Paul Monagle
- Murdoch Children's Research Institute, Parkville, Australia
- The University of Melbourne, Parkville, Australia
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Erenas MM, Ortiz-Gómez I, de Orbe-Payá I, Hernández-Alonso D, Ballester P, Blondeau P, Andrade FJ, Salinas-Castillo A, Capitán-Vallvey LF. Ionophore-Based Optical Sensor for Urine Creatinine Determination. ACS Sens 2019; 4:421-426. [PMID: 30667218 DOI: 10.1021/acssensors.8b01378] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Creatinine is a metabolite present in urine, and its concentration is used to diagnose and monitor kidney performance. For that reason, the development of new sensors to analyze this metabolite and obtain accurate results in a short period of time is necessary. An optical disposable sensor for monitoring creatinine levels in urine is described. The system, based on a new aryl-substituted calix[4]pyrrole synthetic receptor, has an unusual coextraction scheme. Due to the low p Ka values of creatininium (p Ka 4.8), a careful selection of a lipophilic pH indicator that works in acid medium is required. The sensor components were optimized, and the new sensor displays a good response time to creatinine (approximately 3 min) over a wide dynamic range (from 1 × 10-5 to 1 × 10-2 M). Moreover, the optical selectivity coefficients obtained for creatinine over common cations present in urine meet the requirements for real sample measurements. With a good sensor-to-sensor reproducibility (RSD, 5.1-6.9% in the middle of the range), this method provides a simple, quick, cost-effective, and selective alternative to the conventional methodology based on Jaffé's reaction.
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Affiliation(s)
| | | | | | - Daniel Hernández-Alonso
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007 Tarragona, Spain
| | - Pablo Ballester
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007 Tarragona, Spain
- Catalan Institution
for Research and Advanced Studies (ICREA), Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - Pascal Blondeau
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili (URV), C/Marcel·lí Domingo 1, 43007 Tarragona, Spain
| | - Francisco J. Andrade
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili (URV), C/Marcel·lí Domingo 1, 43007 Tarragona, Spain
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Krintus M, Fernandez JA, Chesters C, Colla R, Ford C, Frattolillo D, Köller U, Mairesse J, Jimenez DM, Motol J, Padmore K, Sharrod-Cole H, Sypniewska G. Analytical Performance of 10 High-Volume Clinical Chemistry Assays on the Alinity c System. Lab Med 2019; 50:e1-e8. [PMID: 30247580 DOI: 10.1093/labmed/lmy053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Background Early access for routine testing with the Alinity c clinical chemistry system (Abbot Laboratories) presented the opportunity to characterize the analytical performance of multiple analytes across clinical laboratories in Europe. Methods A total of 8 laboratories from 7 European countries evaluated 10 high-volume chemistry assays on the Alinity c system for imprecision, linearity, and accuracy by method comparison to the routine ARCHITECT (Abbott Laboratories) method. Results Within-run precision was less than 4% coefficient of variation (CV), with total imprecision less than 5.6% CV for 5- and 20-day evaluations. Linearity met expectations, and method comparison showed strong correlation between the Alinity and ARCHITECT methods, with overall linear correlation coefficient between 0.980 to 1.000 and slopes of the regression line between 0.963 and 1.034. Mean percentage difference between the results of assays run on the ARCHITECT and the Alinity ranged between -1.7% and 2.15%. Conclusions Our results demonstrated acceptable key analytical performance across all assays tested at each participating laboratory.
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Affiliation(s)
- Magdalena Krintus
- Department of Laboratory Medicine, Nicolaus Copernicus University, Collegium Medicum, Bydgoszcz, Poland
| | - Jon Ardanza Fernandez
- Department of Biochemistry, Core Laboratory, Hospital Universitario de Álava, Vitoria, Spain
| | | | - Rossana Colla
- Azienda USL di Reggio Emilia, Ospedale di Guastalla U.O. Laboratorio Analisi, Guastalla, Italy
| | - Clare Ford
- Royal Wolverhampton NHS Trust, Wolverhampton, United Kingdom
| | - Daniele Frattolillo
- Azienda USL di Reggio Emilia, Ospedale di Guastalla U.O. Laboratorio Analisi, Guastalla, Italy
| | - Ursula Köller
- Institute for Laboratory Diagnostics, Vienna Hospital Association, Hospital Hietzing, Vienna, Austria
| | | | - Daniel Martinez Jimenez
- Department of Biochemistry, Core Laboratory, Hospital Universitario de Álava, Vitoria, Spain
| | | | | | | | - Grazyna Sypniewska
- Department of Laboratory Medicine, Nicolaus Copernicus University, Collegium Medicum, Bydgoszcz, Poland
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Delanghe JR, De Buyzere ML. Twenty years of European IVD regulations and its aimed traceability - where are we? Clin Chim Acta 2018; 483:263-264. [DOI: 10.1016/j.cca.2018.05.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 05/08/2018] [Indexed: 10/16/2022]
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8
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Guinovart T, Hernández-Alonso D, Adriaenssens L, Blondeau P, Rius FX, Ballester P, Andrade FJ. Characterization of a new ionophore-based ion-selective electrode for the potentiometric determination of creatinine in urine. Biosens Bioelectron 2017; 87:587-592. [DOI: 10.1016/j.bios.2016.08.025] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/29/2016] [Accepted: 08/09/2016] [Indexed: 10/21/2022]
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Jassam N, Weykamp C, Thomas A, Secchiero S, Sciacovelli L, Plebani M, Thelen M, Cobbaert C, Perich C, Ricós C, Paula FA, Barth JH. Post-standardization of routine creatinine assays: are they suitable for clinical applications. Ann Clin Biochem 2016; 54:386-394. [DOI: 10.1177/0004563216664541] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Introduction Reliable serum creatinine measurements are of vital importance for the correct classification of chronic kidney disease and early identification of kidney injury. The National Kidney Disease Education Programme working group and other groups have defined clinically acceptable analytical limits for creatinine methods. The aim of this study was to re-evaluate the performance of routine creatinine methods in the light of these defined limits so as to assess their suitability for clinical practice. Method In collaboration with the Dutch External Quality Assurance scheme, six frozen commutable samples, with a creatinine concentration ranging from 80 to 239 μmol/L and traceable to isotope dilution mass spectrometry, were circulated to 91 laboratories in four European countries for creatinine measurement and estimated glomerular filtration rate calculation. Two out of the six samples were spiked with glucose to give high and low final concentrations of glucose. Results Results from 89 laboratories were analysed for bias, imprecision (%CV) for each creatinine assay and total error for estimated glomerular filtration rate. The participating laboratories used analytical instruments from four manufacturers; Abbott, Beckman, Roche and Siemens. All enzymatic methods in this study complied with the National Kidney Disease Education Programme working group recommended limits of bias of 5% above a creatinine concentration of 100 μmol/L. They also did not show any evidence of interference from glucose. In addition, they also showed compliance with the clinically recommended %CV of ≤4% across the analytical range. In contrast, the Jaffe methods showed variable performance with regard to the interference of glucose and unsatisfactory bias and precision. Conclusion Jaffe-based creatinine methods still exhibit considerable analytical variability in terms of bias, imprecision and lack of specificity, and this variability brings into question their clinical utility. We believe that clinical laboratories and manufacturers should work together to phase out the use of relatively non-specific Jaffe methods and replace them with more specific methods that are enzyme based.
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Affiliation(s)
- Nuthar Jassam
- Department of Clinical Biochemistry, Harrogate District Foundation Trust, Harrogate, UK
| | - Cas Weykamp
- SKML and Department of Clinical Chemistry, Queen Beatrix Hospital, Winterswijk, the Netherlands
| | - Annette Thomas
- WEQAS, Cardiff and Vale University Health Board, Cardiff, UK
| | - Sandra Secchiero
- Biomedical Research Center, Department of Laboratory Medicine, University Hospital of Padova, Padova, Italy
| | - Laura Sciacovelli
- Biomedical Research Center, Department of Laboratory Medicine, University Hospital of Padova, Padova, Italy
| | - Mario Plebani
- Biomedical Research Center, Department of Laboratory Medicine, University Hospital of Padova, Padova, Italy
| | - Marc Thelen
- SKML and Department for Clinical Chemistry, Amphia Hospital, Breda, the Netherlands
| | - Christa Cobbaert
- SKML and Department of Clinical Chemistry, Leiden University Medical Center, Leiden, the Netherlands
| | - Carmen Perich
- Quality Coordinator of Clinical Laboratory, Hospital Vall d’Hebron, Barcelona, Spain
| | - Carmen Ricós
- Spanish Society of Clinical Chemistry and Molecular Pathology (SEQC), Analytical Quality Commission, Barcelona, Spain
| | - Faria A Paula
- Department of Epidemiology, Unity of External Quality Assessment, National Health Institute Doutor Ricardo Jorge, Lisbon, Portugal
| | - Julian H Barth
- Department of Clinical Biochemistry, Leeds Teaching Hospitals Trust, Leeds, UK
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Evaluation of bilirubin interference and accuracy of six creatinine assays compared with isotope dilution–liquid chromatography mass spectrometry. Clin Biochem 2016; 49:274-81. [DOI: 10.1016/j.clinbiochem.2015.10.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 10/23/2015] [Accepted: 10/25/2015] [Indexed: 12/27/2022]
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Hoste L, Deiteren K, Pottel H, Callewaert N, Martens F. Routine serum creatinine measurements: how well do we perform? BMC Nephrol 2015; 16:21. [PMID: 25803560 PMCID: PMC4358903 DOI: 10.1186/s12882-015-0012-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 02/02/2015] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The first aim of the study was to investigate the accuracy and intra-laboratory variation of serum creatinine measurements in clinical laboratories in Flanders. The second purpose was to check the effect of this variation in serum creatinine concentration results on the calculated estimated glomerular filtration rate (eGFR) and the impact on classification of patients into a chronic kidney disease (CKD) stage. METHODS 26 routine instruments were included, representing 13 different types of analyzers from 6 manufacturers and covering all current methodologies (Jaffe, compensated Jaffe, enzymatic liquid and dry chemistry methods). Target values of five serum pools (creatinine concentrations ranging from 35 to 934 μmol/L) were assigned by the gold standard method (ID-GC/MS). RESULTS Intra-run CV (%) (n = 5) and bias (%) from the target values were higher for low creatinine concentrations. Especially Jaffe and enzymatic dry chemistry methods showed a higher error. The calculated eGFR values corresponding with the reported creatinine concentration ranges resulted in a different CKD classification in 47% of cases. CONCLUSIONS Although most creatinine assays claim to be traceable to the gold standard (ID-GC/MS), large inter-assay differences still exist. The inaccuracy in the lower concentration range is of particular concern and may lead to clinical misinterpretation when the creatinine-based eGFR of the patient is used for CKD staging. Further research to improve harmonization between methods is required.
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Affiliation(s)
- Liesbeth Hoste
- Interdisciplinary Research Facility Life Sciences, Katholieke Universiteit Leuven Campus Kortrijk, Kortrijk, Belgium.
| | - Kathleen Deiteren
- Department of Clinical Chemistry and Toxicology, AZ Groeninge Hospital, Reepkaai 4, B8500, Kortrijk, Belgium.
| | - Hans Pottel
- Interdisciplinary Research Facility Life Sciences, Katholieke Universiteit Leuven Campus Kortrijk, Kortrijk, Belgium.
| | - Nico Callewaert
- Department of Clinical Chemistry and Toxicology, AZ Groeninge Hospital, Reepkaai 4, B8500, Kortrijk, Belgium.
| | - Frank Martens
- Department of Clinical Chemistry and Toxicology, AZ Groeninge Hospital, Reepkaai 4, B8500, Kortrijk, Belgium.
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Bargnoux AS, Barrot A, Fesler P, Kuster N, Badiou S, Dupuy AM, Ribstein J, Cristol JP. Evaluation of five immunoturbidimetric assays for urinary albumin quantification and their impact on albuminuria categorization. Clin Biochem 2014; 47:250-3. [PMID: 25072511 DOI: 10.1016/j.clinbiochem.2014.07.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 07/02/2014] [Accepted: 07/18/2014] [Indexed: 11/17/2022]
Abstract
OBJECTIVES The study was designed to evaluate the performance of five automated immunoturbidimetric assays to quantify urinary albumin, each corresponding to a combination of a reagent and an analyzer (Olympus on AU640, Roche on Cobas Integra, Abbott on Architect, Ortho-Clinical Diagnostics Vitros on Fusion and Siemens on Dimension). DESIGN AND METHODS To assess imprecision, albumin was measured in three urinary pools with a mean value of 25, 66 and 131 mg/L. One hundred and eight patient urine samples were then used to compare each turbidimetric method using the Passing-Bablok regression and Bland-Altman analyses. Concordance of the albumin/creatinine ratio (ACR), according to the albuminuria classifications proposed by the KDIGO, was calculated to test the agreement between the different assays. RESULTS All immunoturbidimetric methods evaluated in this study exhibited acceptable imprecision (CV<6%). Mean values for 108 urine samples varied from 0.5 to 762.2 mg/L. Significant differences were found (p<0.05) between all methods except between Olympus and Ortho (p=1.0) and between Abbott and Roche (p=0.12). Regarding the albuminuria categories based on the ACR proposed by the KDIGO, only the classification obtained with the Roche method was significantly different from the four other methods (p<0.001). CONCLUSIONS We demonstrated that all assays were not strictly equivalent which could affect ACR categories in clinical practice, suggesting the need for harmonization of commercial methods.
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Affiliation(s)
- Anne-Sophie Bargnoux
- Laboratoire de Biochimie, CHRU Montpellier, Univ Montpellier 1, Montpellier F-34000, France
| | - Amandine Barrot
- Laboratoire de Biochimie, CHRU Montpellier, Univ Montpellier 1, Montpellier F-34000, France
| | - Pierre Fesler
- Service de Médecine Interne, CHRU Montpellier, Univ Montpellier 1, Montpellier F-34000, France
| | - Nils Kuster
- Laboratoire de Biochimie, CHRU Montpellier, Univ Montpellier 1, Montpellier F-34000, France
| | - Stéphanie Badiou
- Laboratoire de Biochimie, CHRU Montpellier, Univ Montpellier 1, Montpellier F-34000, France
| | - Anne-Marie Dupuy
- Laboratoire de Biochimie, CHRU Montpellier, Univ Montpellier 1, Montpellier F-34000, France
| | - Jean Ribstein
- Service de Médecine Interne, CHRU Montpellier, Univ Montpellier 1, Montpellier F-34000, France
| | - Jean-Paul Cristol
- Laboratoire de Biochimie, CHRU Montpellier, Univ Montpellier 1, Montpellier F-34000, France.
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Calibration and precision of serum creatinine and plasma cystatin C measurement: impact on the estimation of glomerular filtration rate. J Nephrol 2014; 27:467-75. [PMID: 24711159 DOI: 10.1007/s40620-014-0087-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 03/27/2014] [Indexed: 01/31/2023]
Abstract
Serum creatinine (SCr) is the main variable for estimating glomerular filtration rate (GFR). Due to inter-assay differences, the prevalence of chronic kidney disease (CKD) varies according to the assay used, and calibration standardization is necessary. For SCr, isotope dilution mass spectrometry (IDMS) is the gold standard. Systematic differences are observed between Jaffe and enzymatic methods. Manufacturers subtract 0.30 mg/dl from Jaffe results to match enzymatic results ('compensated Jaffe method'). The analytical performance of enzymatic methods is superior to that of Jaffe methods. In the original Modification of Diet in Renal Disease (MDRD) equation, SCr was measured by a Jaffe Beckman assay, which was later recalibrated. A limitation of this equation was an underestimation of GFR in the high range. The Chronic Kidney Disease Epidemiology (CKD-EPI) consortium proposed an equation using calibrated and IDMS traceable SCr. The gain in performance was due to improving the bias whereas the precision was comparable. The CKD-EPI equation performs better at high GFR levels (GFR >60 ml/min/1.73 m(2)). Analytical limitations have led to the recommendation to give a grade (>60 ml/min/1.73 m(2)) rather than an absolute value with the MDRD equation. By using both enzymatic and calibrated methods, this cutoff-grade could be increased to 90 ml/min/1.73 m(2) (with MDRD) and 120 ml/min/1.73 m(2) (with CKD-EPI). The superiority of the CKD-EPI equation over MDRD is analytical, but the precision gain is limited. IDMS traceable enzymatic methods have been used in the development of the Lund-Malmö (in CKD populations) and Berlin Initiative Study equations (in the elderly). The analytical errors for cystatin C are grossly comparable to issues found with SCr. Standardization is available since 2011. A reference method for cystatin C is still lacking. Equations based on standardized cystatin C or cystatin C and creatinine have been proposed. The better performance of these equations (especially the combined CKD-EPI equation) has been demonstrated.
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Park HI, Chae H, Kim M, Lee J, Kim Y. LEGO plot for simultaneous application of multiple quality requirements during trueness verification of quantitative laboratory tests. J Clin Lab Anal 2014; 28:147-56. [PMID: 24395762 DOI: 10.1002/jcla.21659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 06/24/2013] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND We developed a two-dimensional plot for viewing trueness that takes into account potential shift and variable quality requirements to verify trueness using certified reference material (CRM). METHODS Glucose, total cholesterol (TC), and creatinine levels were determined by two kinds of assay in two levels of a CRM. Available quality requirements were collected, codified, and sorted in an ascending order in the plot's header row. Centering on the mean of measured values from CRM, the "mean ± US CLIA '88 allowable total error" was located in the header of the leftmost and rightmost columns. Twenty points were created in intervening columns as potential shifts. Uncertainties were calculated according to regression between certified values and uncertainties of CRM, and positioned in the corresponding columns. Cells were assigned different colors where column and row intersected based on comparison of the 95% confidence interval of the percentage bias with each quality requirement. RESULTS A glucose assay failed to meet the highest quality criteria, for which shift of +0.13-0.14 mmol/l was required. A TC assay met the quality requirement and a shift of ±0.03 mmol/l was tolerable. A creatinine assay also met the quality requirement but any shift was not tolerable. CONCLUSION The plot provides a systematic view of the trueness of quantitative laboratory tests.
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Affiliation(s)
- Hae-il Park
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea; Catholic Laboratory Development and Evaluation Center, Clinical Research Coordinating Center, Catholic Medical Center, Seoul, Republic of Korea
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Evaluation of the impact of standardization process on the quality of serum creatinine determination in Italian laboratories. Clin Chim Acta 2014; 427:100-6. [DOI: 10.1016/j.cca.2013.10.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 09/12/2013] [Accepted: 10/04/2013] [Indexed: 11/18/2022]
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Enzymatic but not compensated Jaffe methods reach the desirable specifications of NKDEP at normal levels of creatinine. Results of the French multicentric evaluation. Clin Chim Acta 2013; 419:132-5. [PMID: 23415696 DOI: 10.1016/j.cca.2013.01.021] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 01/25/2013] [Accepted: 01/25/2013] [Indexed: 11/22/2022]
Abstract
The French Society of Clinical Biochemistry conducted this study to compare the accuracy and performances of the best creatinine enzymatic assays and the compensated Jaffe methods from the same manufacturers. Creatinine was measured in 3 serum pools with creatinine levels of 35.9±0.9 μmol/L, 74.4±1.4 μmol/L, and 97.9±1.7 μmol/L (IDMS determination). The performances of the assays (total error that includes the contribution of bias and imprecision) were evaluated using Monte-Carlo simulations and compared against desirable NKDEP criteria. The enzymatic assays always fell within the desirable total Error of 7.6%. By contrast, this requirement was never obtained for the compensated Jaffe methods at the critical level of 74.4±1.4 μmol/L. Only the compensated Jaffe creatinine on Olympus analyzer reached this specification at 35.9±0.9 and 97.9±1.7 μmol/L levels. This study demonstrates that, despite substantial improvement regarding traceability to the IDMS reference method and precision, compensated Jaffe creatinine methods, by contrast to enzymatic ones, do not reach the desirable specifications of NKDEP at normal levels of creatinine.
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Fernandez-Calle P, Pelaz S, Oliver P, Alcaide MJ, Gomez-Rioja R, Buno A, Iturzaeta JM. The importance of having a flexible scope ISO 15189 accreditation and quality specifications based on biological variation--the case of validation of the biochemistry analyzer Dimension Vista. Biochem Med (Zagreb) 2013; 23:83-95. [PMID: 23457769 PMCID: PMC3900090 DOI: 10.11613/bm.2013.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 12/29/2012] [Indexed: 11/03/2022] Open
Abstract
INTRODUCTION Technological innovation requires the laboratories to ensure that modifications or incorporations of new techniques do not alter the quality of their results. In an ISO 15189 accredited laboratory, flexible scope accreditation facilitates the inclusion of these changes prior to accreditation body evaluation. A strategy to perform the validation of a biochemistry analyzer in an accredited laboratory having a flexible scope is shown. MATERIALS AND METHODS A validation procedure including the evaluation of imprecision and bias of two Dimension Vista analysers 1500 was conducted. Comparability of patient results between one of them and the lately replaced Dimension RxL Max was evaluated. All studies followed the respective Clinical and Laboratory Standards Institute (CLSI) protocols. 30 chemistry assays were studied. Coefficients of variation, percent bias and total error were calculated for all tests and biological variation was considered as acceptance criteria. Quality control material and patient samples were used as test materials. Interchangeability of the results was established by processing forty patients' samples in both devices. RESULTS 27 of the 30 studied parameters met allowable performance criteria. Sodium, chloride and magnesium did not fulfil acceptance criteria. Evidence of interchangeability of patient results was obtained for all parameters except magnesium, NT-proBNP, cTroponin I and C-reactive protein. CONCLUSIONS A laboratory having a well structured and documented validation procedure can opt to get a flexible scope of accreditation. In addition, performing these activities prior to use on patient samples may evidence technical issues which must be corrected to minimize their impact on patient results.
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Affiliation(s)
- Pilar Fernandez-Calle
- Emergency Laboratory, Department of Laboratory Medicine, Hospital Universitario La Paz, Madrid, Spain.
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Clinical evaluation of analytical variations in serum creatinine measurements: why laboratories should abandon Jaffe techniques. BMC Nephrol 2012; 13:133. [PMID: 23043743 PMCID: PMC3504563 DOI: 10.1186/1471-2369-13-133] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 09/23/2012] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Non-equivalence in serum creatinine (SCr) measurements across Dutch laboratories and the consequences hereof on chronic kidney disease (CKD) staging were examined. METHODS National data from the Dutch annual external quality organization of 2009 were used. 144 participating laboratories examined 11 pairs of commutable, value-assigned SCr specimens in the range 52-262 μmol/L, using Jaffe or enzymatic techniques. Regression equations were created for each participating laboratory (by regressing values as measured by participating laboratories on the target values of the samples sent by the external quality organization); area under the curves were examined and used to rank laboratories. The 10th and 90th percentile regression equation were selected for each technique separately. To evaluate the impact of the variability in SCr measurements and its eventual clinical consequences in a real patient population, we used a cohort of 82424 patients aged 19-106 years. The SCr measurements of these 82424 patients were introduced in the 10th and 90th percentile regression equations. The newly calculated SCr values were used to calculate an estimated glomerular filtration rate (eGFR) using the 4-variable Isotope Dilution Mass Spectrometry traceable Modification of Diet in Renal Disease formula. Differences in CKD staging were examined, comparing the stratification outcomes for Jaffe and enzymatic SCr techniques. RESULTS Jaffe techniques overestimated SCr: 21%, 12%, 10% for SCr target values 52, 73 and 94 μmol/L, respectively. For enzymatic assay these values were 0%, -1%, -2%, respectively. eGFR using the MDRD formula and SCr measured by Jaffe techniques, staged patients in a lower CKD category. Downgrading to a lower CKD stage occurred in 1-42%, 2-37% and 12-78.9% of patients for the 10th and 90th percentile laboratories respectively in CKD categories 45-60, 60-90 and >90 ml/min/1.73 m2. Using enzymatic techniques, downgrading occurred only in 2-4% of patients. CONCLUSIONS Enzymatic techniques lead to less variability in SCr measurements than Jaffe techniques, and therefore result in more accurate staging of CKD. Therefore the specific enzymatic techniques are preferably used in clinical practice in order to generate more reliable GFR estimates.
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Abstract
Chronic heart failure and chronic renal failure are at epidemic proportions. These patients have significantly altered cardiac, renal, and all-cause outcomes. Much of the current research has focused on treating these individual organs in isolation. Although there are positive data on outcomes with neurohormonal modulation, they, however, remain underused. At present, data lacks for novel treatment options, while evidence continues to point at significantly worsened prognosis. Current diagnostic tools that detect acute changes in renal function or renal injury appear retrospective, which often hinder meaningful diagnostic and therapeutic decisions. This review is aimed at exploring the importance of accurate assessment of renal function for the heart failure patient by providing a synopsis on cardio-renal physiology and establishing the possibility of novel approaches in bridging the divide.
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Bourguignon L, Ducher M, Matanza D, Bleyzac N, Uhart M, Odouard E, Maire P, Goutelle S. The value of population pharmacokinetics and simulation for postmarketing safety evaluation of dosing guidelines for drugs with a narrow therapeutic index: buflomedil as a case study. Fundam Clin Pharmacol 2011; 26:279-85. [PMID: 22004557 DOI: 10.1111/j.1472-8206.2011.01000.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Population pharmacokinetics and simulation techniques currently play an important role in new drug development. This paper illustrates the potential value of those methods in postmarketing safety assessment, using buflomedil in elderly patients as an example. We retrospectively assessed the risk of buflomedil overdosing associated with the latest dosing recommendations of the French Drug Agency (AFSSAPS). First, buflomedil concentrations measured in 24 elderly patients were analysed with a nonparametric population approach. Then, the pharmacokinetic model was used to perform a 1000-patient Monte Carlo simulation for the two recommended buflomedil dosage regimens. The maximum concentrations calculated after 10 days of therapy were compared with levels observed in reported cases of toxicity to assess the probability of overdosing. A three-compartment model best fit concentration data. Population predictions showed little bias (-0.14 mg/L) and good precision (8.73 mg(2) /L(2)). Overall results of the simulation study showed that the application of the two recommended dosage regimens of buflomedil was associated with overdosing (C(max) > 10 mg/L) and potential toxicity in 2.9% of geriatric patients. In patients with mild renal impairment, who may receive the higher-dosage regimen by therapeutic error, the probability of overdosing was 6.2%. Despite specific dosing recommendations in case of renal impairment, this study shows that the use of buflomedil could be associated with significant risk of overdosing in geriatric patients. Such results might have enhanced decision-making when buflomedil safety was reassessed by AFSSAPS in 2006. The retrospective case of buflomedil illustrates how these methods may be valuable in postmarketing safety evaluation of potentially toxic drugs.
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Fillée C, Vranken G, Othmane M, Philippe M, Allaeys JM, Courbe A, Ruelle JL, Peeters R. Results of the recalibration of creatinine measurement with the modular Beckman Coulter Jaffe creatinine method. Clin Chem Lab Med 2011; 49:1987-99. [PMID: 21801031 DOI: 10.1515/cclm.2011.674] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Serum creatinine is important for detecting the beginning of a decline in kidney function. The Beckman Coulter Jaffe reagents for measuring creatinine have been standardized to the internationally accepted reference method: isotope dilution mass spectrometry (IDMS). The impact of this recalibration on the Beckman Coulter modular or cup (stat) Jaffe method is studied. METHODS Recalibrated Jaffe (calibrator set points IDMS traceable) and classic National Institute of Standards and Technology (NIST) creatinine methods (traceable to NIST 914a) were compared with an enzymatic method (Sentinel, traceable to NIST SRM 967). All measurements were performed on Synchron DxC 800 systems. Imprecision of the routine methods was studied using the Clinical and Laboratory Standards Institute (CLSI) protocols and laboratory quality survey. Thirteen plasma pools, with concentrations < 354 mmol/L, were analyzed with a gas chromatography isotope dilution mass spectrometry (GC-IDMS) method and routine methods. Total error of 8.2% based on biological variability, set on the GC-IDMS values and acceptance criteria (bias < 5%, imprecision < 8% at concentrations ≥ 88.4 mmol/L and a maximum 10% increase in the relative error of estimated glomerular filtration rate (eGFR) of the National Kidney Disease Educational Program (NKDEP) were used for evaluating analytical performance of the routine methods studied. RESULTS After recalibration of the Jaffe method, median bias (mmol/L) decreased from 12.4 (95% CI: 9.1-21.2) to 7.3 (95% CI: 1.5-10.5). Imprecision of the Jaffe method is in agreement with the claim of the manufacturer, namely < 9 mmol/L or < 3% below or above 292 mmol/L. Below creatinine of 88.4 mmol/L, imprecision of the recalibrated Jaffe and enzymatic methods is between 4.1% and 6.9%, and 5.0% and 7.1%, respectively, and significantly different (p = 0.02 for both the Jaffe and enzymatic methods) from the goal, based on biological variability, of 2.7%. For the adult pools, all recalibrated Jaffe and enzymatic results fall within the total error of 8.2%. In the pediatric samples, one-third of the recalibrated Jaffe and three of the six enzymatic results fall within this total error goal. CONCLUSIONS Recalibration significantly reduced bias of the Jaffe method. For pediatric samples, recalibrated Jaffe results do not comply with either the imprecision goal or the total error based on biological variability. Adult recalibrated Jaffe results are in compliance with the goals based on biological variability and with the acceptance criteria from the NKDEP.
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Affiliation(s)
- Catherine Fillée
- Université Catholique de Louvain, Cliniques Universitaires Saint-Luc, Brussels, Belgium
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A multicentric evaluation of IDMS-traceable creatinine enzymatic assays. Clin Chim Acta 2011; 412:2070-5. [PMID: 21803031 DOI: 10.1016/j.cca.2011.07.012] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 07/12/2011] [Accepted: 07/13/2011] [Indexed: 11/22/2022]
Abstract
Chronic kidney disease definition is based on glomerular filtration rate (GFR) estimations which are derived from creatinine-based equations. The accuracy of GFR estimation is thus largely dependent of those of serum creatinine assays. International recommendations highlight the need for traceable creatinine assays. The French Society of Clinical Biochemistry conducted a study for measuring accuracy of creatinine enzymatic methods. This evaluation involved 25 clinical laboratories. Creatinine was measured in serum pools ranging from 35.9±0.9 μmol/L to 174.5±3.1 μmol/L (IDMS determination) using 12 creatinine enzymatic methods. For all creatinine values greater than 74.4±1.4 μmol/L, the bias and imprecision did not exceed 5% and 5.9%, respectively. For the lowest value (35.9±0.9 μmol/L), the bias ranged from -1.8 to 9.9% (with one exception). At this level, the imprecision ranged from 1.9 to 7.8%. The true performances of the assays (couples of bias and relative standard deviation), were evaluated using Monte-Carlo simulations. Most of the assays fall within the maximum Total Error of 12% at all concentrations. This study demonstrates substantial improvements in the calibration, traceability and precision of the enzymatic methods, reaching the NKDEP recommendations. Moreover, most of these assays allowed accurate creatinine measurements for creatinine levels lower than 40 μmol/L.
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Davenport A, Cholongitas E, Xirouchakis E, Burroughs AK. Pitfalls in assessing renal function in patients with cirrhosis--potential inequity for access to treatment of hepatorenal failure and liver transplantation. Nephrol Dial Transplant 2011; 26:2735-42. [PMID: 21690201 DOI: 10.1093/ndt/gfr354] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Serum creatinine is universally used to assess renal function in clinical practice. Creatinine and changes in serum creatinine are used to define acute kidney injury and hepatorenal syndrome (HRS) in patients with progressive liver disease. In addition, creatinine is a key variable in the calculation used to determine priority for liver transplantation in many countries. As there is no universal standardized creatinine assay, there is variation in creatinine determinations between laboratory assays, compounded by assay interference due to chromogens, including bilirubin. This leads to patients with the same actual renal function potentially being offered different treatment options, in terms of access to therapy for HRS and priority waiting time for liver transplantation. Alternative methods for assessing renal function either also tend to overestimate renal function or are too time consuming and expensive to provide practical alternatives for standard clinical practice. Standardization of creatinine assays with readily available reference standards would help minimize interlaboratory variation; of the current creatinine assays, enzymatic creatinine appears more accurate, but even this is inaccurate at high bilirubin concentrations. Further work is required to determine whether interpatient variation can be reduced by correcting creatinine and cystatin measurements for muscle mass.
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Delanghe JR, Cobbaert C, Harmoinen A, Jansen R, Laitinen P, Panteghini M. Focusing on the clinical impact of standardization of creatinine measurements: a report by the EFCC Working Group on Creatinine Standardization. Clin Chem Lab Med 2011; 49:977-82. [PMID: 21428858 DOI: 10.1515/cclm.2011.167] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The recent campaign for standardization of creatinine measurements has been promoted to allow the widespread use of formulas for estimating the glomerular filtration rate (GFR). However, studies on trueness verification and measurement interferences still show disappointing interassay variation of serum creatinine results. Creatinine recalibration has major clinical consequences. In particular, in pediatrics where reference ranges for serum and plasma creatinine are low, calculation of the GFR is problematic when based on alkaline picrate methods because of method non-specificity and the lack of appropriate GFR estimating formulas. Therefore, enzymatic creatinine assays are preferred. In the near future, cystatin C might offer an interesting alternative for GFR estimation. For the calculation of drug doses, the Modification of Diet in Renal Disease study formula generally offers reliable data. However, attention has to be paid to the elderly. Also, the calculation of the Model for End-Stage Liver Disease score, which is used to prioritize patients for liver transplantation, may significantly be influenced by recalibration of creatinine assays. Creatinine restandardization may also affect the current guidelines for referral of chronic kidney disease patients to nephrologists.
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Affiliation(s)
- Joris R Delanghe
- Department of Clinical Chemistry, University Hospital, Gent, Belgium.
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Delanghe JR, Speeckaert MM. Creatinine determination according to Jaffe-what does it stand for? NDT Plus 2011; 4:83-6. [PMID: 25984118 PMCID: PMC4421578 DOI: 10.1093/ndtplus/sfq211] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 12/01/2010] [Indexed: 11/14/2022] Open
Abstract
In 1886, Max Jaffe discovered a reaction of creatinine with picric acid in an alkaline environment. Although the manuscript describes the nature of a precipitate and does not deal with an analytical assay, Jaffe's landmark paper elucidated the basic principles of the creatinine determination method (originally developed by Otto Folin), which became immensely popular and has easily withstood the test of time. Despite the advent of the enzymatic creatinine analysis, the analytical method is still popular due to its simplicity and low cost. As there is no standard recipe for the 'Jaffe' method, much methodological variation has occurred over time. This lack of methodological standardization implies that even in the 21st century, improving the interchangeability of Jaffe results is still an issue.
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Affiliation(s)
- Joris R Delanghe
- Department of Clinical Chemistry, Ghent University Hospital, Gent, Belgium
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Haeckel R, Wosniok W. A new concept to derive permissible limits for analytical imprecision and bias considering diagnostic requirements and technical state-of-the-art. Clin Chem Lab Med 2011; 49:623-35. [DOI: 10.1515/cclm.2011.116] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Flegar-Mestrić Z, Perkov S, Simonović B, Juretić D. Applicability of common reference intervals for serum creatinine concentrations to the Croatian population. Clin Chem Lab Med 2010; 48:231-5. [PMID: 19943808 DOI: 10.1515/cclm.2010.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND In accordance with an ongoing activity for worldwide harmonization based on traceability in laboratory methods, the goal of this study was to validate the applicability of recommended "common" reference intervals for serum creatinine concentrations using a specific enzymatic method to the Croatian population. METHODS The reference group consisted of 240 healthy subjects (120 males and 120 females), between 18 and 74 years of age (median 57 years), who were selected in accordance with the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) recommendations. Creatinine in serum was measured using the creatinine enzymatic assay (Olympus OSR61204) that was standardized to the isotopic dilution mass spectrometry (IDMS) method and National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 967. In addition, creatinine was measured using a kinetic Jaffe method (Olympus OSR6178) standardized to NIST SRM 909b level 2 standard. RESULTS Method comparison between enzymatic creatinine (x) and the Jaffe kinetic method (y) gave the following P/B equation for the entire group (n=240): y=1.00x+17.00; r=0.968. Reference intervals for serum creatinine (central 95th percentiles) obtained using the enzymatic creatinine method ranged from 54 to 107 micromol/L for males and from 50 to 93 micromol/L for females. The IFCC recommended common reference intervals for global applications are 64-104 micromol/L and 49-90 micromol/L for males and females, respectively. CONCLUSIONS Comparability of obtained results confirmed the applicability of recently recommended "common" reference intervals to the Croatian population for all laboratories measuring serum creatinine concentrations using enzymatic methods traceable to the IDMS method and NIST SRM 967.
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Society Spotlight: The European Federation of Clinical Chemistry and Laboratory Medicine. Bioanalysis 2010; 2:47-50. [DOI: 10.4155/bio.09.149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Laboratory medicine is at the heart of modern health care and diagnosis and effective treatment of patients is impossible without high-quality bioanalytical services. The European Federation of Clinical Chemistry and Laboratory Medicine is a professional federation working to ensure high standards across the discipline in all European countries. This article describes our work in science, education and professional development.
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Kooman JP. Estimation of renal function in patients with chronic kidney disease. J Magn Reson Imaging 2009; 30:1341-6. [DOI: 10.1002/jmri.21970] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Arzideh F, Wosniok W, Haeckel R. Reference limits of plasma and serum creatinine concentrations from intra-laboratory data bases of several German and Italian medical centres: Comparison between direct and indirect procedures. Clin Chim Acta 2009; 411:215-21. [PMID: 19914230 DOI: 10.1016/j.cca.2009.11.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 11/02/2009] [Accepted: 11/07/2009] [Indexed: 01/14/2023]
Abstract
BACKGROUND The current dogma of establishing intra-laboratory reference limits (RLs) and their periodical reviewing cannot be fulfilled by most laboratories due to the expenses involved. Thus, most laboratories adopt external sources for their RLs often neglecting the problems of transferability. Therefore, several attempts were undertaken to derive RLs from the large data pools stored in modern laboratory information systems. These attempts were further developed to a more sophisticated indirect procedure. The new model can be considered a combined approach because it pre-excludes some subjects by direct criteria. In the current study, the new concept was applied to estimate RLs for serum and plasma creatinine from several German and Italian laboratories. METHODS A smoothed kernel density function was estimated for the distribution of the total mixed data of the sample group (combined data of non-diseased and diseased subjects). It was assumed that the "central" part of the distribution of all data represents the non-diseased ("healthy") population. The central part was defined by truncation points using an optimisation method, and was used to estimate a Gaussian distribution of the values of presumably non-diseased subjects after Box-Cox transformation of the empirical data. This distribution was now considered as the distribution of the non-diseased subgroup. The percentiles of this parametrical distribution were calculated to obtain RLs. RESULTS RLs determined by the indirect combined decomposition technique led to similar RLs as the classical direct method. Furthermore, the RLs obtained from 14 laboratories in 2 different European regions reflected the well-known differences of various analytical procedures. Stratification for gender and age was necessary. With rising age, an increase of the upper RL and of the reference range was observed. Hospitalization appeared also to affect the RLs. The new approach led to RLs in an artificially mixed population of diseased and non-diseased subjects (selected by clinical criteria) which were identical to RLs determined by a direct method applied to the non-diseased subgroup. CONCLUSIONS The proposed strategy of combining exclusion criteria with a resolution technique led to plausible retrospective RLs from intra-laboratory data pools for creatinine. Differences between laboratories were mainly due to the well-known bias of the different analytical procedures.
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Affiliation(s)
- Farhad Arzideh
- Institut für Statistik, Universität Bremen, Bremen, Germany
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