Effects of α-Thalassemia on HbA_1c Measurement

α-Thalassemia is a benign condition that is often present in patients with diabetes mellitus. Here, we evaluated the effects of different genotypes α-thalassemia on HbA_1c measurement.

A total of 189 samples from nondiabetic patients were analyzed. HbA_1c analysis was performed by ion-exchange high-performance liquid chromatography, boronate affinity HPLC, immunoassay, and capillary electrophoresis. Fasting glucose, fructosamin, and HbA₂ were also performed. All samples were confirmed by genotyping for thalassemia.

In patients with two or three functional α-genes, HbA_1c values were not significantly different from those of controls (P > 0.05); however, in individuals with α-thalassemia with one functional α-gene (i.e., HbH disease), HbA_1c levels were significantly different from those of controls (P < 0.01). HbA_1c values were significantly lower in individuals with HbH disease than in control individuals and patients in the other two α-thalassemia groups. For patients with HbH disease, there were no significant differences in the four HbA_1c measurement systems (P > 0.05).

In this study, HbA_1c values in samples from individuals with two or three functional α-genes basically reflected the normal mean blood glucose level, while those in samples from individuals with one functional α-gene did not.