Incidental Detection of Hemoglobin Variants During Evaluation of HbA1c

HemoglobinA1c (HbA1c) is used to diagnose Diabetes mellitus and monitor glycemic control over the previous eight to twelve weeks in diabetic patients. Detection of HbA1c by cation exchange-high performance liquid chromatography (CE-HPLC) gives a chromatogram by which abnormal hemoglobin variants are also picked up. Some of these may interfere with HbA1c values affecting clinical management. Due to increased inter-state migration as well as medical tourism, there is a high possibility of finding various hemoglobin variants in any part of India. We did a prospective analysis over 1.5 years, of the hemoglobin variants detected during all the HbA1c runs. The HbA1c was tested on Bio-Rad D10 dual HbA2/F/A1c platform, which uses the CE-HPLC method. Every chromatogram was carefully studied to look for unknown peaks. The samples showing unknown peaks >6% were re-run in extended HbA2/F mode to categorize the hemoglobin variants. We had 9595 HbA1c samples, of which 70 cases showed a variant window. There were 40 males and 30 females, age ranging from 28 to 76 years. The different hemoglobin variants detected were HbD, HbE and HbS in heterozygous state, high HbF (with a differential diagnosis of HPFH heterozygous and delta-beta thalassemia heterozygous), HbE homozygous, HbQ heterozygous and HbJ heterozygous. We conclude that in the process of monitoring glycemic control using HbA1c, we can also pick-up hemoglobin variants. Hence, it is essential to review HbA1c graphs, so that the diagnosis of hemoglobin variants is not missed and the HbA1c reported is reliable.