A glycosylated hemoglobin (HbA1) test was used to evaluate the role of dialysate glucose in the development of carbohydrate intolerance and hyperlipidemia in chronic hemodialysis patients and chronic peritoneal dialysis patients. HbA1 levels were significantly elevated in all groups of patients. HbA1 levels were not ameliorated with 8 weeks of glucose-free hemodialysis. There was no correlation between HbA1 and serum glucose, triglycerides, or cholesterol. Thus, HbA1 elevation cannot be explained solely by glucose reabsorption from dialysate. This test is helpful in the detection of carbohydrate intolerance, but its usefulness in evaluation of hyperlipidemia of dialysis patients is uncertain.