Correlation of HbA1C, glycated serum proteins and albumin, and fructosamine with the 24-h glucose profile of insulin-dependent pregnant diabetics.

To assess the value of various methods for long-term follow-up of diabetic patients, we compared the concentrations of fructosamine in serum with those of various glycated proteins: hemoglobin (HbA1C), total serum proteins (G-prot), and albumin (G-alb), assayed in 30 pregnant insulin-dependent diabetics every two weeks after initial determination of a 24-h blood glucose profile. HbA1C correlated best with the 24-h glucose profile during the succeeding 10-35 days (r = 0.65-0.68, P less than 0.001). G-prot and G-alb correlated nearly as well as HbA1C 10-20 days after the glucose profile (r = 0.54-0.64, P less than 0.01-0.001), but only weakly after 25-35 days. Values for fructosamine did not correlate significantly with the glucose profile 10-35 days after it (r = 0.23-0.36). Evidently the fructosamine assay is not an adequate alternative to HbA1C, G-alb, or G-prot as an index to long-term control of blood glucose in such patients.