INCREASED FETAL HEMOGLOBIN IN INSULIN-TREATED DIABETES-MELLITUS CONTRIBUTES TO THE IMPRECISION OF GLYCOHEMOGLOBIN MEASUREMENTS

An increased prevalence of fetal hemoglobin (HbF) has been described i n pediatric insulin-dependent patients. The popular electroendosmotic method for glycohemoglobin includes HbF. In an adult population compri sing 50 insulin-treated and 57 non-insulin-treated diabetic patients a nd 57 control subjects, we measured HbF by HPLC and measured glycohemo globin by both HPLC and an electroendosmotic method. Of the insulin-tr eated patients, 46% had concentrations of HbF greater-than-or-equal-to 0.5%, compared with 25% of non-insulin-treated patients and 23% of co ntrols (P <0.02). In the insulin-treated patients, the two glycohemogl obin methods correlated best when the HPLC measurements included HbF ( r = 0.92 vs r = 0.84). Fructosamine concentrations correlated best wit h glycohemoglobin concentrations determined by methods that accounted for HbF. The true between-batch CV of the electroendosmotic assay incr eased (from 4.33% to 8.33%) when variable interpatient HbF concentrati ons were included. Thus, HbF must be considered when interpreting glyc ohemoglobin measured by an electroendosmotic method and when comparing it with other measures of glycemic control.