Hemoglobin C (HbC) trait is a heterozygous hemoglobinopathy common in West Africa. Due to interference with the HPLC assay, heterozygous hemoglobinopathies such as HbC trait may lead to readings for A1C which are artefactually low. Therefore, the value of A1C as a diagnostic test may be compromised. Glycated albumin (GA) may be an effective alternate to A1C because it is a nonfasting measure of glycemia which is not impacted by Hb variants. No study has focused on HbC trait and evaluated the ability of A1C and GA to detect glucose tolerance status. Our goals were to evaluate the diagnostic efficacy of A1C and GA in the detection of dysglycemia in the 4% (13/366) of African-born blacks enrolled in the Africans in America Study who had HbC trait documented by hemoglobin electrophoresis. OGTT was performed in the 13 participants (age 37±7y (mean±SD), BMI 26.9±3.4 kg/m2). Glucose tolerance status was defined by the OGTT. The ability of A1C≥5.7% and GA≥14.2% to diagnose dysglycemia was evaluated. Both A1C≥5.7% and GA≥14.2% represent the upper quartile cut-off for their distribution in the Africans in America cohort. Mean A1C was 4.8±0.7%, range 3.1- 5.6%. Mean GA was 13.9±1.3%, range 11.9 - 15.4%. Thirty-nine % (5/13) of the participants had prediabetes and 8% (1/13) had diabetes. However, A1C was <5.7% in all participants. Therefore, for A1C sensitivity and specificity were 0% and 100% resp. In contrast, for GA the sensitivity and specificity were 83% and 71%, resp. Although the number of individuals with HbC trait in our cohort was small, our findings suggest that GA may be an important screening test to be used in populations with a high prevalence of HbC trait.
S.M. Briker: None. M.F. Horlyck-Romanovsky: None. R. Mugeni: None. J.Y. Aduwo: None. C. DuBose: None. A.E. Sumner: None.