HEMOGLOBIN A(1C) MEASUREMENT FOR DIABETES AMONG SUBJECTS WITH A PREVIOUS HISTORY OF IMPAIRED GLUCOSE-TOLERANCE

Haemoglobin A(1c) (HbA(1c)) measurement for diagnosis of diabetes and impaired glucose tolerance (IGT) was assessed during a prospective stu dy of subjects with IGT; 183 of the 207 IGT persons underwent the seco nd oral glucose tolerance tests (OGTT) 2.1 years, on the average, afte r the first tests. HbA(1c) was administered to every participant befor e the second OGTTs. The results of HbA(1c) were compared with those of the second OGTTs. The sensitivity of HbA(1c) test was 71% for diabete s and 41% for IGT, when the specificity was 93% at a cutoff point of 4 .81%. The conclusion is that the HbA,, test is moderately sensitive fo r diabetes but insensitive for IGT, when it is specific. However, it m ay be useful for selecting and reducing the total number of subjects r eferred to 2-h OGTTs in a follow-up study of subjects with IGT, if the rate of progression to diabetes is not high.