Impact of Lipemia and Hemoglobin S Variant on HbA1c Measurement: A Comparison of Diazyme Enzymatic Method and Capillary Electrophoresis

Abstract

Background: Glycated hemoglobin (HbA1c) is the standard indicator for assessing long-term blood glucose control. However, its accuracy can be affected by lipemia and hemoglobin variants. Objectives: The present study aimed to compare the reliability of enzymatic methods and capillary electrophoresis (CE) under varying lipemic conditions. Methods: In this analytical study, blood samples from 30 patients with type 2 diabetes (16 women and 14 men) were examined under four conditions: Baseline, mild lipemia (5 g/L), severe lipemia (20 g/L), and after washing with 0.9% normal saline. HbA1c was measured using the enzymatic method (Mindray BS480 device) and CE (Capillarys 3 Tera system). Results: Under mild lipemia conditions, both methods demonstrated acceptable accuracy (P > 0.05). In severe lipemia, the enzymatic method showed a significant false elevation in HbA1c levels (P < 0.01), while the CE method remained stable. After saline washing, HbA1c levels measured by the enzymatic method increased further (P < 0.01), whereas a significant decrease was observed with the CE method (P = 0.02). Conclusions: In conditions of severe lipemia and in the presence of the HbS variant, CE proves to be a more reliable method for measuring HbA1c. Saline washing failed to reduce lipemic interference in the enzymatic method and even led to increased measurement errors. This suggests that residual matrix effects following washing can still impact the performance of the enzymatic method. In contrast, CE, with its higher resistance to matrix interferences, is a more dependable option for use in complex clinical samples.