Effect of Hemoglobin E on Measurement of Hemoglobin A1c by Fire Different Methods

Abstract

Patients with hemoglobin (Hb) variants may produce false hemoglobin A1c (HbA1c) measurement leading to misdiagnosis or mistreatment. This study aimed to evaluate the effects of Hb E on five different HbA1c analytical principles. HbA1c levels of 160 EDTA blood samples including Hb type A2A (N=51), heterozygous Hb E (N=104), and homozygous Hb E (N=5) were analyzed by immunoturbidimetric method, HPLC, LPLC, enzymatic assay, and boronate affinity chromatography. The strong positive correlations of HbA1c levels measured by all assays were observed (r=0.797 to 0.962, p<0.001). The HbA1c results analyzed by immunoassay and enzymatic assay were significant higher than boronate affinity chromatography (p<0.05), in Hb type A2A and heterozygous Hb E samples. However, these differenced between assays in each hemoglobin typing were comparable. The results by using HPLC were under reportable range in homozygous Hb E group. The mean differences between HbA1c results analyzed by using LPLC and other 4 testes methods were significantly higher in heterozygous Hb E samples with Hb F>2%, compared to samples with Hb F <=2% (p<0.05). This work showed a good comparability of HbA1c assays, although, some methods were influenced by high levels of Hb E and Hb F. Therefore, Hb E and Hb F are interfering factors that laboratories must be aware when reporting results if its presence is suspected.