A case of undetectable glycosylated hemoglobin

Cation-exchange high-performance liquid chromatography separates hemoglobin species based on charge differences. Since the glycosylated hemoglobin [HbA1c] test is based on normal hemoglobin, hemoglobinopathies can affect the test by altering the normal process of glycation of HbA to A1C, producing an abnormal peak on chromatogram or making the erythrocytes more prone to hemolysis, thereby decreasing the time for glycosylation to occur and producing a falsely low A1C result. A 51-year-old male presented with complaint of generalized weakness. HbA1c test done to rule out abnormal glucose tolerance revealed undetectable levels. He had low hemoglobin, microcytic red cell indices, 86.2 % of hemoglobin E (corrected A2), and minor elevation of fetal hemoglobin. This case is significant for the incidental discovery of HbE homozygosity in an apparently healthy and active person, through incidental finding of undetectable levels of HbA1c.