Identification of hemoglobin variants in samples received for glycated hemoglobin testing

In 2010 Singapore's National Health Survey reported 11.3% of the population between 18-69 years of age with diabetes, compared to 8.2% in 2006. This increasing trend reinforces the dependence on HbA(1c) for management of glycemic control.

To determine the incidence of hemoglobin variants received from our diabetic population who are attending the National University Hospital for testing of their HbA(1c) and determine whether the hemoglobin variant caused an interpretation issue, we reviewed all chromatograms from patients sending a sample for HbA(1c) analysis for a three-month period. Analysis was performed on the Variant II using the HbA(2)/HbA(1c) Dual program.

Our sub-analysis identified 2 cases of α thalassemia, 2 cases of β thalassemia; 5 cases of hemoglobin E variant homozygous, 1 case of hemoglobin J variant, 110 cases of hemoglobin E, 7 cases of hemoglobin S, 1 case of hemoglobin C and 1 case of hemoglobin D, all heterozygous. HbA(1c) results could be confidently reported in all cases except the homozygote variant and the hemoglobin J variant.

Overall we obtained a prevalence of 2.3% of hemoglobin variants in our diabetic population being screened by HbA(1c) using Variant II.