Comparison of HbA₁ and Fructosamine in Diagnosis of Glucose-Tolerance Abnormalities

Total glycosylated hemoglobin (HbA₁) and fructosamine were evaluated as screening tools for detection of glucose-tolerance abnormalities in 144 asymptomatic subjects undergoing a 75-g oral glucose tolerance test. Subjects were classified according to World Health Organization criteria as having normal (n = 78), impaired (n = 40), or diabetic (n = 26) glucose tolerance. We found good specificity for HbA₁ and fructosamine (100 and 97%, respectively) but low sensitivity (15 and 19%, respectively). At the intersection of the curves of sensitivity and specificity drawn from various thresholds of normality, both sensitivity and specificity were 75% for HbA₁ and 55% for fructosamine. Thus, neither HbA₁ nor fructosamine seems to be suitable for the diagnosis of mild abnormalities in glucose tolerance.