We would like to thank the College of American Pathologists for allowing us to use their survey data.
Author contributions: All the authors have accepted responsibility for the entire content of this 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.
1. Westgard JO, Westgard SA. Assessing quality on the Sigma scale from proficiency testing and external quality assessment surveys. Clin Chem Lab Med 2015;53:1531–5. Search in Google Scholar
2. The International Expert Committee. International Expert Committee report on the role of the A1C assay in the diagnosis of diabetes. Diabetes Care 2009;32:1327–34. Search in Google Scholar
3. Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002;346:393–403. Search in Google Scholar
5. Weykamp C, John G, Gillery P, English E, Ji Linong J, Lenters-Westra E, et al. Investigation of two models to set and evaluate quality targets for HbA1c: biological variation and Sigma-metrics. Clin Chem 2015;61:752–9. Search in Google Scholar
©2016 by De Gruyter