Performances of capillary electrophoresis and HPLC methods in HbA1c determination: diagnostic accuracy in HbS and HbD-Iran variants' presence.

Background: Glycated hemoglobin (HbA1c) provides a useful estimate of mean glycemia in patients with diabetes and is directly related to risks for diabetes complications. The aim of this study is to compare a capillary electrophoresis method and two high-performance liquid chromatography (HPLC) cation-exchange analyzers (Variant II (Bio-Rad Laboratories, Inc., Hercules, CA) and G8 (Tosoh Biosciences, San Francisco, CA)) to identify the most reliable method in Hb variants' presence.

Methods: Measurements of HbA1c were carried out in blood samples from 200 Tor Vergata Hospital patients, using G8 Tosoh, and from 107 San Filippo Neri Hospital patients, using Variant II Bio-Rad methods. All samples were analyzed by Capillarys 2 Flex Piercing (FP; Sebia, Lisses, France).

Results: There was a good concordance between the results of capillary electrophoresis and HPLC methods (R(2) = 0.99, P < 0.0001 for G8 HPLC; R(2) = 0.99, P < 0.0001 for Variant II HPLC). During the study, we observed that some Hb variants, HbS and HbD-Iran, can alter the HbA1c level.

Conclusions: Since the HbA1c test is now recommended for diagnosing diabetes, and minimal variation of the concentration affects the clinical therapy, it is very important that the results are reliable and interference-free. Capillarys 2-FP analyzer is suitable for this purpose and sometimes it showed some advantages with respect to the HPLC analyzers tested, especially when Hb variants are present.