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Abildgaard A, Knudsen CS, Bjerg LN, Lund S, Støy J. Reply to letter from Mayfield et al. regarding "Lot variation and inter-device differences contribute to poor analytical performance of the DCA Vantage™ HbA 1c POCT instrument in a true clinical setting". Clin Chem Lab Med 2023; 61:e8-e10. [PMID: 36281702 DOI: 10.1515/cclm-2022-0915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 09/20/2022] [Indexed: 12/15/2022]
Affiliation(s)
- Anders Abildgaard
- Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus N, Denmark
| | | | - Lise Nørkjær Bjerg
- Department of Clinical Biochemistry, Regional Hospital Central Jutland, Viborg, Denmark
| | - Sten Lund
- Steno Diabetes Center Aarhus, Aarhus, University Hospital, Aarhus N, Denmark
| | - Julie Støy
- Steno Diabetes Center Aarhus, Aarhus, University Hospital, Aarhus N, Denmark
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2
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Tan H, Liu T, Zhou T. Exploring the role of eRNA in regulating gene expression. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2022; 19:2095-2119. [PMID: 35135243 DOI: 10.3934/mbe.2022098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
eRNAs as the products of enhancers can regulate gene expression via various possible ways, but which regulation way is more reasonable is debatable in biology, and in particular, how eRNAs impact gene expression remains unclear. Here we introduce a mechanistic model of gene expression to address these issues. This model considers three possible regulation ways of eRNA: Type-I by which eRNA regulates transcriptional activity by facilitating the formation of enhancer-promoter (E-P) loop, Type-II by which eRNA directly promotes the mRNA production rate, and mixed regulation (i.e., the combination of Type-I and Type-II). We show that with the increase of the E-P loop length, mRNA distribution can transition from unimodality to bimodality or vice versa in all the three regulation cases. However, in contrast to the other two regulations, Type-II regulation can lead to the highest mean mRNA level and the lowest mRNA noise, independent of the E-P loop length. These results would not only reveal the essential mechanism of how eRNA regulates gene expression, but also imply a new mechanism for phenotypic switching, namely the E-P loop can induce phenotypic switching.
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Affiliation(s)
- Heli Tan
- School of Financial Mathematics and Statistics, Guangdong University of Finance, Guangzhou 510521, China
| | - Tuoqi Liu
- School of Mathematics, Sun Yat-Sen University, Guangzhou 510275, China
| | - Tianshou Zhou
- School of Mathematics, Sun Yat-Sen University, Guangzhou 510275, China
- Guangdong Province Key Laboratory of Computational Science, Guangzhou 510275, China
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3
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Li Z, Li C, Pu H, Pang X, Wang Y, Zhang D, Lei M, Cheng X, Zhao Y, Lu G, Ding Y, Cai L, Liu Z, Zhang T, You D. Trajectories of perioperative serum carcinoembryonic antigen and colorectal cancer outcome: A retrospective, multicenter longitudinal cohort study. Clin Transl Med 2021; 11:e293. [PMID: 33634994 PMCID: PMC7818970 DOI: 10.1002/ctm2.293] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/05/2021] [Accepted: 01/07/2021] [Indexed: 01/15/2023] Open
Affiliation(s)
- Zhenhui Li
- Department of RadiologyYunnan Cancer Hospitalthe Third Affiliated Hospital of Kunming Medical UniversityYunnan Cancer CenterKunmingChina
- Department of Colorectal SurgeryYunnan Cancer HospitalYunnan Cancer Centerthe Third Affiliated Hospital of Kunming Medical UniversityKunmingChina
| | - Chunxia Li
- Department of BiostatisticsSchool of Public HealthCheeloo College of MedicineShandong UniversityJinanChina
| | - Hongjiang Pu
- Department of Colorectal SurgeryYunnan Cancer HospitalYunnan Cancer Centerthe Third Affiliated Hospital of Kunming Medical UniversityKunmingChina
- Department of OncologyDazhou Central HospitalDazhouChina
| | - Xiaolin Pang
- Department of Radiotherapythe Sixth Affiliated Hospital of Sun Yat‐sen UniversityGuangzhouChina
| | - Yingyi Wang
- Department of RadiologyZhuhai People's HospitalZhuhai Hospital Affiliated with Jinan UniversityZhuhaiChina
| | - Dafu Zhang
- Department of RadiologyYunnan Cancer Hospitalthe Third Affiliated Hospital of Kunming Medical UniversityYunnan Cancer CenterKunmingChina
| | - Ming Lei
- Department of Clinical Laboratory MedicineYunnan Cancer HospitalYunnan Cancer Centerthe Third Affiliated Hospital of Kunming Medical UniversityKunmingChina
| | - Xianshuo Cheng
- Department of Colorectal SurgeryYunnan Cancer HospitalYunnan Cancer Centerthe Third Affiliated Hospital of Kunming Medical UniversityKunmingChina
| | - Yanrong Zhao
- Department of Colorectal SurgeryYunnan Cancer HospitalYunnan Cancer Centerthe Third Affiliated Hospital of Kunming Medical UniversityKunmingChina
| | - Guiyu Lu
- Department of Colorectal SurgeryYunnan Cancer HospitalYunnan Cancer Centerthe Third Affiliated Hospital of Kunming Medical UniversityKunmingChina
| | - Yingying Ding
- Department of RadiologyYunnan Cancer Hospitalthe Third Affiliated Hospital of Kunming Medical UniversityYunnan Cancer CenterKunmingChina
| | - Le Cai
- School of Public HealthKunming Medical UniversityKunmingChina
| | - Zaiyi Liu
- Department of RadiologyGuangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Tao Zhang
- Department of BiostatisticsSchool of Public HealthCheeloo College of MedicineShandong UniversityJinanChina
| | - Dingyun You
- School of Public HealthKunming Medical UniversityKunmingChina
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4
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Bachmann MO, Lewis G, John WG, Turner J, Dhatariya K, Clark A, Pascale M, Sampson M. Determinants of diagnostic discordance for non-diabetic hyperglycaemia and Type 2 diabetes using paired glycated haemoglobin measurements in a large English primary care population: cross-sectional study. Diabet Med 2019; 36:1478-1486. [PMID: 31420897 DOI: 10.1111/dme.14111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/14/2019] [Indexed: 12/25/2022]
Abstract
AIM To investigate factors influencing diagnostic discordance for non-diabetic hyperglycaemia and Type 2 diabetes. METHODS Some 10 000 adults at increased risk of diabetes were screened with HbA1c and fasting plasma glucose (FPG). The 2208 participants with initial HbA1c ≥ 42 mmol/mol (≥ 6.0%) or FPG ≥ 6.1 mmol/l were retested after a median 40 days. We compared the first and second HbA1c results, and consequent diagnoses of non-diabetic hyperglycaemia and Type 2 diabetes, and investigated predictors of discordant diagnoses. RESULTS Of 1463 participants with non-diabetic hyperglycaemia and 394 with Type 2 diabetes on first testing, 28.4% and 21.1% respectively had discordant diagnoses on repeated testing. Initial diagnosis of non-diabetic hyperglycaemia and/or impaired fasting glucose according to both HbA1c and FPG criteria, or to FPG only, made reclassification as Type 2 diabetes more likely than initial classification according to HbA1c alone. Initial diagnosis of Type 2 diabetes according to both HbA1c and FPG criteria made reclassification much less likely than initial classification according to HbA1c alone. Age, and anthropometric and biological measurements independently but inconsistently predicted discordant diagnoses and changes in HbA1c . CONCLUSIONS Diagnosis of non-diabetic hyperglycaemia or Type 2 diabetes with a single measurement of HbA1c in a screening programme for entry to diabetes prevention trials is unreliable. Diagnosis of non-diabetic hyperglycaemia and Type 2 diabetes should be confirmed by repeat testing. FPG results could help prioritise retesting. These findings do not apply to people classified as normal on a single test, who were not retested.
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Affiliation(s)
- M O Bachmann
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - G Lewis
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - W G John
- Department of Clinical Biochemistry, Norfolk and Norwich University Hospitals NHS Trust, Norwich, UK
| | - J Turner
- Elsie Bertram Diabetes Centre, Norfolk and Norwich University Hospitals NHS Trust, Norwich, UK
| | - K Dhatariya
- Elsie Bertram Diabetes Centre, Norfolk and Norwich University Hospitals NHS Trust, Norwich, UK
| | - A Clark
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - M Pascale
- Elsie Bertram Diabetes Centre, Norfolk and Norwich University Hospitals NHS Trust, Norwich, UK
| | - M Sampson
- Elsie Bertram Diabetes Centre, Norfolk and Norwich University Hospitals NHS Trust, Norwich, UK
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5
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Biological variation of resting measures of ventilation and gas exchange in a large healthy cohort. Eur J Appl Physiol 2019; 119:2033-2040. [DOI: 10.1007/s00421-019-04190-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/11/2019] [Indexed: 10/26/2022]
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6
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Discordance in glycemic categories and regression to normality at baseline in 10,000 people in a Type 2 diabetes prevention trial. Sci Rep 2018; 8:6240. [PMID: 29674706 PMCID: PMC5908912 DOI: 10.1038/s41598-018-24662-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/19/2018] [Indexed: 12/11/2022] Open
Abstract
The world diabetes population quadrupled between 1980 and 2014 to 422 million and the enormous impact of Type 2 diabetes is recognised by the recent creation of national Type 2 diabetes prevention programmes. There is uncertainty about how to correctly risk stratify people for entry into prevention programmes, how combinations of multiple 'at high risk' glycemic categories predict outcome, and how the large recently defined 'at risk' population based on an elevated glycosylated haemoglobin (HbA1c) should be managed. We identified all 141,973 people at highest risk of diabetes in our population, and screened 10,000 of these with paired fasting plasma glucose and HbA1c for randomisation into a very large Type 2 diabetes prevention trial. Baseline discordance rate between highest risk categories was 45.6%, and 21.3-37.0% of highest risk glycaemic categories regressed to normality between paired baseline measurements (median 40 days apart). Accurate risk stratification using both fasting plasma glucose and HbA1c data, the use of paired baseline data, and awareness of diagnostic imprecision at diagnostic thresholds would avoid substantial overestimation of the true risk of Type 2 diabetes and the potential benefits (or otherwise) of intervention, in high risk subjects entering prevention trials and programmes.
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7
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Aarsand AK, Røraas T, Fernandez-Calle P, Ricos C, Díaz-Garzón J, Jonker N, Perich C, González-Lao E, Carobene A, Minchinela J, Coşkun A, Simón M, Álvarez V, Bartlett WA, Fernández-Fernández P, Boned B, Braga F, Corte Z, Aslan B, Sandberg S. The Biological Variation Data Critical Appraisal Checklist: A Standard for Evaluating Studies on Biological Variation. Clin Chem 2017; 64:501-514. [PMID: 29222339 DOI: 10.1373/clinchem.2017.281808] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 11/16/2017] [Indexed: 11/06/2022]
Abstract
BACKGROUND Concern has been raised about the quality of available biological variation (BV) estimates and the effect of their application in clinical practice. A European Federation of Clinical Chemistry and Laboratory Medicine Task and Finish Group has addressed this issue. The aim of this report is to (a) describe the Biological Variation Data Critical Appraisal Checklist (BIVAC), which verifies whether publications have included all essential elements that may impact the veracity of associated BV estimates, (b) use the BIVAC to critically appraise existing BV publications on enzymes, lipids, kidney, and diabetes-related measurands, and (c) apply metaanalysis to deliver a global within-subject BV (CVI) estimate for alanine aminotransferase (ALT). METHODS In the BIVAC, publications were rated as A, B, C, or D, indicating descending compliance for 14 BIVAC quality items, focusing on study design, methodology, and statistical handling. A D grade indicated that associated BV estimates should not be applied in clinical practice. Systematic searches were applied to identify BV studies for 28 different measurands. RESULTS In total, 128 publications were identified, providing 935 different BV estimates. Nine percent achieved D scores. Outlier analysis and variance homogeneity testing were scored as C in >60% of 847 cases. Metaanalysis delivered a CVI estimate for ALT of 15.4%. CONCLUSIONS Application of BIVAC to BV publications identified deficiencies in required study detail and delivery, especially for statistical analysis. Those deficiencies impact the veracity of BV estimates. BV data from BIVAC-compliant studies can be combined to deliver robust global estimates for safe clinical application.
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Affiliation(s)
- Aasne K Aarsand
- Norwegian Porphyria Centre, Laboratory of Clinical Biochemistry, Haukeland University Hospital, Bergen, Norway; .,Norwegian Quality Improvement of Laboratory Examinations (NOKLUS), Haraldsplass Deaconess Hospital, Bergen, Norway
| | - Thomas Røraas
- Norwegian Quality Improvement of Laboratory Examinations (NOKLUS), Haraldsplass Deaconess Hospital, Bergen, Norway
| | - Pilar Fernandez-Calle
- La Paz University Hospital, Madrid, Spain.,Spanish Society of Laboratory Medicine (SEQC-ML), Analytical Quality Commission, Barcelona, Spain
| | - Carmen Ricos
- Spanish Society of Laboratory Medicine (SEQC-ML), Analytical Quality Commission, Barcelona, Spain
| | - Jorge Díaz-Garzón
- La Paz University Hospital, Madrid, Spain.,Spanish Society of Laboratory Medicine (SEQC-ML), Analytical Quality Commission, Barcelona, Spain
| | - Niels Jonker
- Certe, Wilhelmina Ziekenhuis Assen, Assen, the Netherlands
| | - Carmen Perich
- Spanish Society of Laboratory Medicine (SEQC-ML), Analytical Quality Commission, Barcelona, Spain.,Clinic Laboratory Hospital Vall d'Hebron, Barcelona, Spain
| | - Elisabet González-Lao
- Spanish Society of Laboratory Medicine (SEQC-ML), Analytical Quality Commission, Barcelona, Spain.,Catlab, Clinic Laboratory, Mutua Terrassa University Hospital, Barcelona, Spain
| | - Anna Carobene
- Servizio Medicina di Laboratorio, Ospedale San Raffaele, Milan, Italy
| | - Joana Minchinela
- Spanish Society of Laboratory Medicine (SEQC-ML), Analytical Quality Commission, Barcelona, Spain.,Metropolitana Nord Unified Laboratory (LUMN), Germans Trias i Pujol University Hospital, Badalona, Spain
| | | | - Margarita Simón
- Spanish Society of Laboratory Medicine (SEQC-ML), Analytical Quality Commission, Barcelona, Spain.,Laboratory de l'Alt Penedés, l'Anoia i el Garraf, Barcelona, Spain
| | - Virtudes Álvarez
- Spanish Society of Laboratory Medicine (SEQC-ML), Analytical Quality Commission, Barcelona, Spain
| | | | | | - Beatriz Boned
- Spanish Society of Laboratory Medicine (SEQC-ML), Analytical Quality Commission, Barcelona, Spain.,Royo Villanova Hospital, Zaragoza, Spain
| | - Federica Braga
- Research Centre for Metrological Traceability in Laboratory Medicine (CIRME), University of Milan, Milan, Italy
| | - Zoraida Corte
- Spanish Society of Laboratory Medicine (SEQC-ML), Analytical Quality Commission, Barcelona, Spain.,San Agustin University Hospital, Aviles, Asturias, Spain
| | - Berna Aslan
- Institute for Quality Management in Healthcare (IQMH), Centre for Proficiency Testing, Toronto, ON, Canada
| | - Sverre Sandberg
- Norwegian Porphyria Centre, Laboratory of Clinical Biochemistry, Haukeland University Hospital, Bergen, Norway.,Norwegian Quality Improvement of Laboratory Examinations (NOKLUS), Haraldsplass Deaconess Hospital, Bergen, Norway.,Department of Global Health and Primary Care, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway
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8
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Pimentel AL, Camargo JL. Variability of glycated hemoglobin levels in the first year post renal transplantation in patients without diabetes. Clin Biochem 2017; 50:997-1001. [DOI: 10.1016/j.clinbiochem.2017.07.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 07/18/2017] [Accepted: 07/19/2017] [Indexed: 10/19/2022]
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9
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Hirst JA, McLellan JH, Price CP, English E, Feakins BG, Stevens RJ, Farmer AJ. Performance of point-of-care HbA1c test devices: implications for use in clinical practice - a systematic review and meta-analysis. Clin Chem Lab Med 2017; 55:167-180. [PMID: 27658148 DOI: 10.1515/cclm-2016-0303] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 07/19/2016] [Indexed: 12/25/2022]
Abstract
BACKGROUND Point-of-care (POC) devices could be used to measure hemoglobin A1c (HbA1c) in the doctors' office, allowing immediate feedback of results to patients. Reports have raised concerns about the analytical performance of some of these devices. We carried out a systematic review and meta-analysis using a novel approach to compare the accuracy and precision of POC HbA1c devices. METHODS Medline, Embase and Web of Science databases were searched in June 2015 for published reports comparing POC HbA1c devices with laboratory methods. Two reviewers screened articles and extracted data on bias, precision and diagnostic accuracy. Mean bias and variability between the POC and laboratory test were combined in a meta-analysis. Study quality was assessed using the QUADAS2 tool. RESULTS Two researchers independently reviewed 1739 records for eligibility. Sixty-one studies were included in the meta-analysis of mean bias. Devices evaluated were A1cgear, A1cNow, Afinion, B-analyst, Clover, Cobas b101, DCA 2000/Vantage, HemoCue, Innovastar, Nycocard, Quo-Lab, Quo-Test and SDA1cCare. Nine devices had a negative mean bias which was significant for three devices. There was substantial variability in bias within devices. There was no difference in bias between clinical or laboratory operators in two devices. CONCLUSIONS This is the first meta-analysis to directly compare performance of POC HbA1c devices. Use of a device with a mean negative bias compared to a laboratory method may lead to higher levels of glycemia and a lower risk of hypoglycaemia. The implications of this on clinical decision-making and patient outcomes now need to be tested in a randomized trial.
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10
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Zhou R, Wang W, Song ZX, Tong Q, Wang QT. Evaluation of a new hemoglobin A1c analyzer for point-of-care testing. J Clin Lab Anal 2017; 32. [PMID: 28220976 DOI: 10.1002/jcla.22172] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 01/17/2017] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND There has been an increasing desire for the use of point-of-care testing (POCT) by both primary care clinicians and patients. This study aimed to evaluate the performance of a new POCT analyzer for hemoglobin A1c (HbA1c) testing. METHODS We assessed the accuracy, precision, and linearity of the POCT HbA1c analyzer (A1C EZ 2.0) with the Tosoh G8 Analyzer as comparative instrument, following the Clinical and Laboratory Standards Institute (CLSI) protocols. We evaluated sensitivity and specificity of the A1C EZ 2.0 in the clinical diagnosis of diabetes among 842 subjects from 79 communities in Beijing, China. RESULTS Using regression analysis, the slope of the A1C EZ 2.0 vs the Tosoh G8 Analyzer was 0.9938, with an intercept of 0.0964 and a concordance correlation coefficient of 0.978. For precision, the reproducibility of CV (CVT ) were 3.7% and 2.7% at a lower (36 mmol/mol (5.4%)) and higher (107 mmol/mol (11.9%)) level of HbA1c respectively. The area under the receiver operating characteristic (ROC) curve for clinical diagnosis of diabetes was 0.911 with the HbA1c cut-off value of 44 mmol/mol (6.14%). At the HbA1c level of 48 mmol/mol (6.5%), the sensitivity and specificity were76.1% and 86.6%. CONCLUSION The A1C EZ 2.0 has a high accuracy and precision, with a wide range of linearity, compared to a comparative laboratory instrument. It met analytical quality specifications and could be suitable for the clinical management of diabetes mellitus.
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Affiliation(s)
- Rui Zhou
- Department of Clinical Laboratory, Beijing Chao-Yang Hospital Affiliated to Capital Medical University, Beijing, China
| | - Wei Wang
- Department of Blood Transfusion, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Zhi-Xin Song
- Department of Clinical Laboratory, Fang-Shan-Liang-Xiang Hospital, Beijing, China
| | - Qing Tong
- Beijing Center for Clinical Laboratories, Beijing, China
| | - Qing-Tao Wang
- Department of Clinical Laboratory, Beijing Chao-Yang Hospital Affiliated to Capital Medical University, Beijing, China.,Beijing Center for Clinical Laboratories, Beijing, China
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11
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Abstract
This study uses three unique data sets to show the state of the art of hemoglobin A1c (HbA1c) analyzers in a range of settings and compares their performance against the international guidance set by the International Federation of Clinical Chemistry and Laboratory Medicine task force for HbA1c standardization. The data are used to show the effect of tightening those criteria, and the study serves as a guide to the practical implementation of the sigma-metrics approach in a range of clinical settings.
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12
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Dijkstra A, Lenters-Westra E, de Kort W, Bokhorst AG, Bilo HJG, Slingerland RJ, Vos MJ. Whole Blood Donation Affects the Interpretation of Hemoglobin A1c. PLoS One 2017; 12:e0170802. [PMID: 28118412 PMCID: PMC5261611 DOI: 10.1371/journal.pone.0170802] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 01/11/2017] [Indexed: 11/25/2022] Open
Abstract
Introduction Several factors, including changed dynamics of erythrocyte formation and degradation, can influence the degree of hemoglobin A1c (HbA1c) formation thereby affecting its use in monitoring diabetes. This study determines the influence of whole blood donation on HbA1c in both non-diabetic blood donors and blood donors with type 2 diabetes. Methods In this observational study, 23 non-diabetic blood donors and 21 blood donors with type 2 diabetes donated 475 mL whole blood and were followed prospectively for nine weeks. Each week blood samples were collected and analyzed for changes in HbA1c using three secondary reference measurement procedures. Results Twelve non-diabetic blood donors (52.2%) and 10 (58.8%) blood donors with type 2 diabetes had a significant reduction in HbA1c following blood donation (reduction >-4.28%, P < 0.05). All non-diabetic blood donors with a normal ferritin concentration predonation had a significant reduction in HbA1c. In the non-diabetic group the maximum reduction was -11.9%, in the type 2 diabetes group -12.0%. When eligible to donate again, 52.2% of the non-diabetic blood donors and 41.2% of the blood donors with type 2 diabetes had HbA1c concentrations significantly lower compared to their predonation concentration (reduction >-4.28%, P < 0.05). Conclusion Patients with type 2 diabetes contributing to whole blood donation programs can be at risk of falsely lowered HbA1c. This could lead to a wrong interpretation of their glycemic control by their general practitioner or internist.
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Affiliation(s)
| | - Erna Lenters-Westra
- Department of Clinical Chemistry, Isala Hospital, Zwolle, the Netherlands
- European Reference Laboratory for Glycohemoglobin, Isala Hospital, Zwolle, the Netherlands
| | - Wim de Kort
- Department Donor Studies, Sanquin, Amsterdam, the Netherlands
- Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Arlinke G. Bokhorst
- Department Medical Donor Affairs, Sanquin Blood Bank Division, Amsterdam, the Netherlands
| | - Henk J. G. Bilo
- Department of Internal Medicine, Isala Hospital, Zwolle, the Netherlands
- Department of Internal Medicine, University Medical Center Groningen, Groningen, the Netherlands
| | - Robbert J. Slingerland
- Department of Clinical Chemistry, Isala Hospital, Zwolle, the Netherlands
- European Reference Laboratory for Glycohemoglobin, Isala Hospital, Zwolle, the Netherlands
| | - Michel J. Vos
- Department of Clinical Chemistry, Isala Hospital, Zwolle, the Netherlands
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13
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Penttilä I, Penttilä K, Holm P, Laitinen H, Ranta P, Törrönen J, Rauramaa R. Methods, units and quality requirements for the analysis of haemoglobin A 1c in diabetes mellitus. World J Methodol 2016; 6:133-142. [PMID: 27376018 PMCID: PMC4921944 DOI: 10.5662/wjm.v6.i2.133] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 11/16/2015] [Accepted: 03/25/2016] [Indexed: 02/06/2023] Open
Abstract
The formation of glycohemoglobin, especially the hemoglobin A1c (HbA1c) fraction, occurs when glucose becomes coupled with the amino acid valine in the β-chain of Hb; this reaction is dependent on the plasma concentration of glucose. Since the early 1970s it has been known that diabetics display higher values OF HbA1C because they have elevated blood glucose concentrations. Thus HbA1c has acquired a very important role in the treatment and diagnosis of diabetes mellitus. After the introduction of the first quantitative measurement OF HbA1C, numerous methods for glycohemoglobin have been introduced with different assay principles: From a simple mini-column technique to the very accurate automated high-pressure chromatography and lastly to many automated immunochemical or enzymatic assays. In early days, the results of the quality control reports for HbA1c varied extensively between laboratories, therefore in United States and Canada working groups (WG) of the Diabetes Controls and Complications Trial (DCCT) were set up to standardize the HbA1c assays against the DCCT/National Glycohemoglobin Standardization Program reference method based on liquid chromatography. In the 1990s, the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) appointed a new WG to plan a reference preparation and method for the HBA1c measurement. When the reference procedures were established, in 2004 IFCC recommended that all manufacturers for equipment used in HbA1c assays should calibrate their methods to their proposals. This led to an improvement in the coefficient of variation (CV%) associated with the assay. In this review, we describe the glycation of Hb, methods, standardization of the HbA1c assays, analytical problems, problems with the units in which HbA1c values are expressed, reference values, quality control aspects, target requirements for HbA1c, and the relationship of the plasma glucose values to HbA1c concentrations. We also note that the acceptance of the mmol/mol system for HbA1c as recommended by IFCC, i.e., the new unit and reference ranges, are becoming only slowly accepted outside of Europe where it seems that expressing HbA1c values either only in per cent units or with parallel reporting of percent and mmol/mol will continue. We believe that these issues should be resolved in the future and that it would avoid confusion if mmol/mol unit for HbA1c were to gain worldwide acceptance.
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14
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HbA1c and Risks of All-Cause and Cause-Specific Death in Subjects without Known Diabetes: A Dose-Response Meta-Analysis of Prospective Cohort Studies. Sci Rep 2016; 6:24071. [PMID: 27045572 PMCID: PMC4820688 DOI: 10.1038/srep24071] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 03/18/2016] [Indexed: 12/17/2022] Open
Abstract
Whether HbA1c levels are associated with mortality in subjects without known diabetes remains controversial. Moreover, the shape of the dose–response relationship on this topic is unclear. Therefore, a dose–response meta-analysis was conducted. PubMed and EMBASE were searched. Summary hazard ratios (HRs) were calculated using a random-effects model. Twelve studies were included. The summary HR per 1% increase in HbA1c level was 1.03 [95% confidence interval (CI) = 1.01–1.04] for all-cause mortality, 1.05 [95% CI = 1.02–1.07) for cardiovascular disease (CVD) mortality, and 1.02 (95% CI = 0.99–1.07) for cancer mortality. After excluding subjects with undiagnosed diabetes, the aforementioned associations remained significant for CVD mortality only. After further excluding subjects with prediabetes, all aforementioned associations presented non-significance. Evidence of a non-linear association between HbA1c and mortality from all causes, CVD and cancer was found (all Pnon-linearity < 0.05). The dose–response curves were relatively flat for HbA1c less than around 5.7%, and rose steeply thereafter. In conclusion, higher HbA1c level is associated with increased mortality from all causes and CVD among subjects without known diabetes. However, this association is driven by those with undiagnosed diabetes or prediabetes. The results regarding cancer mortality should be treated with caution due to limited studies.
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15
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Carobene A. Reliability of biological variation data available in an online database: need for improvement. Clin Chem Lab Med 2016; 53:871-7. [PMID: 25883200 DOI: 10.1515/cclm-2014-1133] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 03/12/2015] [Indexed: 11/15/2022]
Abstract
BACKGROUND Biological variation (BV) data enable assessment of the significance of changes in serial measurements observed within a subject and are used to set analytical quality specifications. This data is available in a database held in Westgard website (http://www.westgard.com/biodatabase1.htm). Some limitations of this data, however, have been identified in recent published reviews. The aim of this paper is to show the reliability of the published BV data and to identify ongoing works to address some of its limitations. METHODS The BV data currently hosted on the Westgard website was examined. Distribution of measurands stratified by the number of cited references upon which the database entry is based and the distribution of papers stratified by publication year, are shown. Moreover, BV data available in literature for glycated hemoglobin, C-reactive protein, glycated albumin, alanine aminotransferase, aspartate aminotransferase and γ-glutamyl transferase are evaluated. RESULTS The results obtained show that most BV data come just from a few papers or only one paper and that a lot of publications are dated, therefore this data is too obsolete to be used. Furthermore critical review of the BV database highlights a number of factors that might impact on the reliability of the BV data entries and translation into current practice. CONCLUSIONS A number of issues clearly undermine the value of the current database. These issues are being considered by the European Federation of Clinical Chemistry and Laboratory Medicine, biological variation working group, in collaboration with a Spanish group responsible for the database updating.
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Qi Z, Chen Y, Zhang L, Ma X, Wang F, Cheng Q, Du J, Hao Y, Chi S, Cui W. Biological variations of thirteen plasma biochemical indicators. Clin Chim Acta 2016; 452:87-91. [DOI: 10.1016/j.cca.2015.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/06/2015] [Accepted: 11/06/2015] [Indexed: 10/22/2022]
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Biological variations of seven tumor markers. Clin Chim Acta 2015; 450:233-6. [DOI: 10.1016/j.cca.2015.08.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 08/27/2015] [Accepted: 08/27/2015] [Indexed: 11/20/2022]
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Weykamp C, John G, Gillery P, English E, Ji L, Lenters-Westra E, Little RR, Roglic G, Sacks DB, Takei I. Investigation of 2 models to set and evaluate quality targets for hb a1c: biological variation and sigma-metrics. Clin Chem 2015; 61:752-9. [PMID: 25737535 PMCID: PMC4946649 DOI: 10.1373/clinchem.2014.235333] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/29/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND A major objective of the IFCC Task Force on Implementation of HbA1c Standardization is to develop a model to define quality targets for glycated hemoglobin (Hb A1c). METHODS Two generic models, biological variation and sigma-metrics, are investigated. We selected variables in the models for Hb A1c and used data of external quality assurance/proficiency testing programs to evaluate the suitability of the models to set and evaluate quality targets within and between laboratories. RESULTS In the biological variation model, 48% of individual laboratories and none of the 26 instrument groups met the minimum performance criterion. In the sigma-metrics model, with a total allowable error (TAE) set at 5 mmol/mol (0.46% NGSP), 77% of the individual laboratories and 12 of 26 instrument groups met the 2σ criterion. CONCLUSIONS The biological variation and sigma-metrics models were demonstrated to be suitable for setting and evaluating quality targets within and between laboratories. The sigma-metrics model is more flexible, as both the TAE and the risk of failure can be adjusted to the situation-for example, requirements related to diagnosis/monitoring or international authorities. With the aim of reaching (inter)national consensus on advice regarding quality targets for Hb A1c, the Task Force suggests the sigma-metrics model as the model of choice, with default values of 5 mmol/mol (0.46%) for TAE and risk levels of 2σ and 4σ for routine laboratories and laboratories performing clinical trials, respectively. These goals should serve as a starting point for discussion with international stakeholders in the field of diabetes.
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Affiliation(s)
- Cas Weykamp
- Department of Clinical Chemistry and European Reference Laboratory, Location Queen Beatrix Hospital, Winterswijk, the Netherlands;
| | - Garry John
- Norfolk and Norwich University Hospital, Norwich, UK
| | - Philippe Gillery
- Laboratory of Pediatric Biology and Research, University Hospital of Reims, Reims, France
| | - Emma English
- School of Medicine, University of Nottingham, Royal Derby Hospital Site, Derby, UK
| | - Linong Ji
- Peking University People's Hospital, Beijing, China
| | - Erna Lenters-Westra
- Department of Clinical Chemistry, Isala Clinics, Zwolle, the Netherlands; European Reference Laboratory, Location Isala, Zwolle, the Netherlands
| | - Randie R Little
- Departments of Pathology and Child Health, University of Missouri School of Medicine, Columbia, MO
| | - Gojka Roglic
- Department of Management of Noncommunicable Diseases, World Health Organization, Geneva, Switzerland
| | - David B Sacks
- Department of Laboratory Medicine, NIH, Bethesda, MD
| | - Izumi Takei
- Diabetes and Endocrine Department, Ichikawa General Hospital, Ichikawa, Japan
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