The Value of HbA 1 and Fructosamine in Predicting Impaired Glucose Tolerance—An Alternative to OGTT to Detect Diabetes Mellitus or Gestational Diabetes

Glycosylated haemoglobin and glycosylated serum protein concentrations (fructosamine) have been monitored in patients suspected of diabetes mellitus ( n = 183), in pregnant women suspected of gestational diabetes ( n = 250) and in control groups ( n = 184). The response to the standard 75 g oral glucose tolerance test was used to confirm or reject the diagnosis, using different criteria for detection of diabetes mellitus compared to detection of gestational diabetes. A slightly higher sensitivity was observed for fructosamine compared to glycosylated haemoglobin to detect impaired glucose tolerance (52 vs 44%) or gestational diabetes (17% vs 8%). For detection of diabetic oral glucose tolerance no difference was observed between glycosylated haemoglobin and fructosamine; sensitivity for both parameters was 67%. The results suggest that fructosamine is slightly more sensitive in detecting borderline-abnormal glucose tolerance, whereas no differences are observed for detection of clearly abnormal oral glucose tolerance tests.