Glycosylated haemoglobin and glycosylated albumin: evaluation of different methods in diabetic control.

The levels of glycosylated haemoglobins and albumin were determined in 56 diabetic patients aged between 5 and 19 years. The glycohaemoglobin levels were measured by two different methods, cation-exchange chromatography and a colorimetric chemical method. The glycosylated albumin levels were measured by a chemical method in plasma albumin purified with Affi-gel Blue. The results were compared with other indicators such as blood glucose and urinary glucose. The postprandial blood glucose levels were well correlated with the levels of glycoproteins: glycohaemoglobin by the column method (r = 0.886), glycohaemoglobin by the chemical method (r = 0.72) and glycoalbumin (r = 0.662). The urinary levels of glucose showed a weak correlation with blood glucose levels (r = 0.214) and with glycoalbumin (r = 0.298), but no correlation with glycohaemoglobin. Significant correlations between the changes of glycosylated albumin levels and glycohaemoglobin were found (r = 0.78). The result of the comparison of the chemical method with the column method for glycohaemoglobin determination showed a high correlation between the values (r = 0.95). There were significant differences in glycosylated protein levels between normal and diabetics. There were also significant differences in glycohaemoglobin and glycoalbumin values between fairly managed and poorly managed groups of diabetics. Of the three parameters, glycoalbumin, glycohaemoglobin and plasma glucose, the greatest absolute changes were found in the levels of glycoalbumin.