Comparison of glycosylated hemoglobin and fasting plasma glucose with two-hour post-load plasma glucose in the detection of diabetes mellitus.

In the course of a screening for diabetes mellitus in the Hôtel-Dieu Hospital in Paris, from September 15, 1981 to April 1, 1984, an oral glucose tolerance test and a measurement of glycosylated hemoglobin were performed on 333 outpatients. With two-hour plasma glucose as a reference, the sensitivities of glycosylated hemoglobin, fasting plasma glucose, and a combination of glycosylated hemoglobin and fasting plasma glucose equal, respectively, 60.0%, 52.0%, and 40.0%; the specificities 90.9%, 98.7%, and 99.4%; the predictive value for a positive diagnosis 34.9%, 76.5%, and 83.3%. If one takes into account the implications of diabetes mellitus, especially its economic and psychosociologic consequences, it seems better for diagnosis--from a public health point of view--to use tests with a high degree of specificity and a high predictive value for a positive diagnosis, such as the combination of fasting plasma glucose and glycosylated hemoglobin, than tests with a good sensitivity but poor specificity. In the long term, validation of glycosylated hemoglobin as a diagnostic test for asymptomatic diabetes mellitus will be obtained only by reference to unquestionable criteria of the disease, determined by longitudinal survey.