Glycosylated serum protein levels in diabetic and nondiabetic pregnant patients: an indicator of short-term glycemic control in the diabetic patient.

Measurement of the level of nonenzymatic glycosylation of blood proteins with more rapid turnover times than hemoglobin has been suggested as an indicator of time-averaged glucose control in nonpregnant diabetic patients. Using affinity chromatography, we have measured the levels of glycosylated serum proteins during pregnancy in 14 normal volunteers and 15 insulin-dependent diabetic patients. No relationship was noted between the percentage of glycosylated serum proteins in serum from normal patients and the gestational age at the time of sampling in the second and third trimesters of pregnancy. When the relative frequency distribution of glycosylated serum protein levels in normal patients was compared with that in diabetic patients, a significant difference was noted between the two groups, with a higher percentage of glycosylated serum protein levels in diabetic patients being at elevated values compared to those in normal patients. Normal patients had measured glycosylated serum protein levels of 12.5% +/- 2.2% whereas diabetic patients had glycosylated serum protein levels of 14.0% +/- 3.6%. When peak fasting serum glucose and high Chemstrip glucose levels were compared with glycosylated serum proteins in the diabetic population, a significant correlation for each was noted. The best correlation resulted from a comparison of an average Chemstrip glucose level (mean of 49 glucose values during the previous week) and the glycosylated serum protein value obtained at the end of that week. This inexpensive assay can be adapted to any clinical laboratory and should provide an objective means to evaluate short-term glycemic control, complementing the evaluation provided by self-glucose monitoring (immediate control) and intermittent assay of glycosylated hemoglobin (long-term control).