We had three main findings: (1) HbA1c failed to diagnose Abnl-GT in individuals with G6PD-D, including individuals who had T2D; (2) G6PD-D lowered HbA1C levels by ~0.9% on average and (3) for the detection of G6PD-D, the enzymatic assay was more informative than genotyping. This evidence concerns the gene G6PD and type 2 diabetes mellitus.