Influence of RBC Indices on HbA1c Measurement by Capillary Electrophoresis and HPLC Methods

Background: HbA1c is the gold standard of diabetic surveys to monitor the long-term glycemic control. Anemia is cited as a major confounder to HbA1c analysis; however, the effect of RBC indices influences on HbA1c analysis is not known. The aim of this study is to compare ion-exchange high-performance liquid chromatography, and capillary electrophoresis to evaluate the influence of RBC parameters on HbA1c values in anemia patients. Methods: Erythrocyte parameters were collected from the 307 randomly selected specimens from the Hematology division. HbA1c was measured on the same specimen using Tosoh G8 and Capillarys 2 Flex Piercing on the same day. Results: There is acceptable concordance between the results of capillary electrophoresis and HPLC methods (R-2 = 0.953, p < 0.001). However, significant differences in HbA1c value between the two assay methods were obtained in the patients with abnormal RBC indices (p < 0.001). Conclusions: Our results demonstrated HbA1c differences were significantly different in the patients with low Hb (<= 8 g/dL) and high RDW-CV (>= 13.7%). It is suggested that in the analysis of HbAlc level in anemia patients, simultaneous testing for hemoglobin level is needed. In addition, development of a new reference value of HBA1c for patients with severe anemia should be considered.