Micro-chromatographic measurement of hemoglobin A1 in uremia

In an investigation of the reliability of the measurement of HbA1 by microcolumn chromatography for monitoring glucose metabolism in chronic renal failure, measurements were made in 96 uremic patients. Thirty-one patients were undialyzed, 42 patients including 10 with primary diabetes mellitus were on hemodialysis, and 23 patients were on continuous ambulatory peritoneal dialysis (6 with primary diabetes mellitus). Significantly raised HbA1 values were observed in all groups, whether their glucose tolerance was normal or decreased. Azotemia was not statistically correlated either with HbA1 values, or with glucose tolerance. Dialyzed primary diabetic patients showed HbA1 levels which were significantly higher than those in non-diabetics, but some overlap was evident. The results suggest that the increased values of HbA1 in uremic patients depend on the plasma concentration of either glucose which leads to the formation of glycosylated Hb or of urea which leads to the formation of carbamylated Hb. These are indistinguishable by microcolumn chromatography. Therefore this method cannot be recommended for evaluation of glucose metabolism in uremic patients.