Influence of hemoglobin E on measurement of hemoglobin A1c by immunoassays

Abstract

Background: Many assays used for HbA1c measurement can be interfered by hemoglobin variants. Hemoglobin E is one of the most common variant. Effect of HbE on high performance liquid chromatography was widely reported but not on immunoassay. Objective: To determine the effect of hemoglobin E on HbA1c values by immunoassay methods. Material and methods: Two immunoassays were used for measurement of HbA1c in samples with hemoglobin type as A2A (normal controls, n = 60), EA (heterozygous hemoglobin E, n = 151), and EE (homozygous hemoglobin E, n = 43). Results within each assay and each hemoglobin typing group were compared. Mann-Whitney U test, Pearson's correlation and linear regression analysis were used. Results: There were significant differences of HbA1c values between normal controls and hemoglobin E-contained samples. Correlation between two assays was worse in the presence of hemoglobin E comparing to normal controls. Conclusion: Hemoglobin E can affect the immunoassays used for HbA1c measurement. Further studies are needed to understand the mechanism of interference. © 2008 Elsevier Ireland Ltd. All rights reserved.