Low proportions of glycosylated hemoglobin associated with hemoglobin S and hemoglobin C

Using a cation-exchange chromatographic method, we found normal or subnormal values for glycosylated hemoglobin in a few diabetic patients with persistent hyperglycemia. Subsequent investigations revealed that these unexpected results had originated from black patients with diabetes. In view of common occurrence of abnormal hemoglobins in the Negro population, we subjected blood preparations to electrophoresis on cellulose acetate and acrylamide gel. The results have shown the presence of hemoglobin S or hemoglobin C in each patient. When allowance was made for the percentage of the abnormal hemoglobin, the "corrected values" of glycosylated hemoglobin increased to the diabetic range. Furthermore, the corrected values agreed well with the "expected values" calculated from a regression line correlating fasting blood glucose concentrations and proportions of glycosylated hemoglobin in more than 300 diabetics with no evidence of hemoglobinopathy. We conclude that in diabetic patients presenting with hemoglobin S or hemoglobin C, there is a considerable decrease in the values for glycosylated hemoglobin as measured by cation-exchange chromatographic methods, and that this decrease is proportional to the percentage of the abnormal hemoglobin.