Abstract
Background:
External quality assessment/proficiency test (EQA/PT) organizers play an important role in monitoring the performance of HbA1c measurements. With increasing quality of the assays, HbA1c is increasingly used for diagnosis of diabetes and the demands on EQA/PT organizers themselves are rising constantly. EQA organizers in Germany (INSTAND), Belgium (WIV/IPV), and the Netherlands (SKML) organized a program with commutable samples and target values assigned with the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) reference system. The aim of this project was to confirm the logistic feasibility of organizing synchronically in the three countries, an accuracy-based EQA program with fresh whole blood, to investigate the performance of HbA1c assays within and across countries and manufacturers, and to review the EQA acceptance limits.
Methods:
Throughout 2015, ten fresh whole blood samples were supplied to the participants. Aggregated results were evaluated according to the IFCC model for quality targets at four levels: overall, per country, per manufacturer, and per country per manufacturer.
Results:
Robust results in summer and winter demonstrated the feasibility of organizing an EQA with fresh whole blood samples in three countries. The overall performances, as well as the performance for each country were very similar: results fell within the IFCC criteria. Although substantial differences between results from different manufacturers were present, the performances of laboratories using tests of the same manufacturer were strikingly similar in the three countries, suggesting that the quality of HbA1c assays is for the most part manufacturer- related. The improved design of the EQA program also suggested that acceptance limits for performance can be reduced to approximately 8%.
Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: None declared.
Employment or leadership: None declared.
Honorarium: None declared.
Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.
References
1. American Diabetes Association. Standards of medical care in diabetes. 2011. Diabetes Care 2011;34(Suppl 1):S11–61.10.2337/dc11-S011Search in Google Scholar PubMed PubMed Central
2. Sacks DB, Arnold M, Bakris GL, Bruns DE, Horvath AR, Kirkman MS, et al. Guidelines and recommendations for laboratory analysis in the diagnosis and management of diabetes mellitus. Clin Chem 2011;57:e1–47.10.1373/clinchem.2010.161596Search in Google Scholar PubMed
3. Nathan D. On behalf of the Expert Committee. International Expert Committee on the role of A1c assay in the diagnosis of diabetes. Diabetes Care 2009;32:1327–34.10.2337/dc09-1777Search in Google Scholar
4. Mosca A, Paleari R, Carobene A, Weykamp C, Ceriotti F. Performance of glycated hemoglobin (HbA1c) methods evaluated with EQAS studies using fresh blood samples: still space for improvements. Clin Chim Acta 2015;451:305–9.10.1016/j.cca.2015.10.014Search in Google Scholar PubMed
5. EN ISO/IEC 17043, Conformity assessment –General requirements for proficiency testing. International Organization for Standardization (Geneva, Switzerland).Search in Google Scholar
6. ISO 13528, Statistical methods for use in proficiency testing by interlaboratory comparisons. International Organization for Standardization (Geneva, Switzerland).Search in Google Scholar
7. Jeppson JO, Kobold U, Barr J, Finke A, Hoelzel W, Hoshino T, et al. Approved IFCC reference method for measurement of HbA1c in human blood. Clin Chem Lab Med 2002;40:78–89.10.1515/CCLM.2002.016Search in Google Scholar PubMed
8. Kaiser P, Akerboom T, Molnar P, Reinauer H. Modified HPLC-electrospray ionization/mass spectrometry method for HbA1c based on IFCC reference measurement procedure. Clin Chem 2008;54:1018–22.10.1373/clinchem.2007.100875Search in Google Scholar PubMed
9. Evaluation of measurement data – Guide to the expression of uncertainty in measurement. BIPM Joint Comm Guides Metrol 100:2008.Search in Google Scholar
10. Weykamp C, John G, Gillery P, English E, Li Linong, Lenters-Westra E, et al. Investigation of 2 models to set and evaluate quality targets for HbA1c: biological variation and sigma-metrics. Clin Chem 2015;61:752–9.10.1373/clinchem.2014.235333Search in Google Scholar PubMed PubMed Central
11. Richtlinie der Bundesärztekammer zur Qualitätssicherung laboratoriums-medizinischer Untersuchungen. Dtsch Arztebl 2014;38:A1583–618.10.1515/labmed-2013-0040Search in Google Scholar
12. Mosca A, Weykamp C. Feasibility of an EQAS for HbA1c in Italy using fresh blood samples. Clin Chem Lab Med 2014;52:e151–3.10.1515/cclm-2014-0084Search in Google Scholar PubMed
13. Weykamp C, Mosca A, Gillery P, Panteghini M. The analytical goals for hemoglobin A(1c) measurement in IFCC units and national Glycohemoglobin Standardization Program Units are different. Clin Chem 2011;57:1204–6.10.1373/clinchem.2011.162719Search in Google Scholar PubMed
14. Miller WG, Jones GR, Horowitz GL, Weykamp C. Proficiency testing/external quality assessment: current challenges and future directions. Clin Chem 2011;57:1677–80.10.1373/clinchem.2011.168641Search in Google Scholar PubMed
Supplemental Material:
The online version of this article (DOI: 10.1515/cclm-2016-0123) offers supplementary material, available to authorized users.
©2016 Walter de Gruyter GmbH, Berlin/Boston
