[Impaired glucose tolerance--current concept and its classification].

In this paper, I pointed out a few basic problems related to oral glucose tolerance test (OGTT), and reviewed historical perspective focusing on the changes of diagnostic criteria of glucose intolerance and the application of OGTT to the diagnosis of diabetes mellitus. I also commented on the historical values of the NIH proposal on "the diagnosis of diabetes mellitus and other categories of glucose tolerance" (1979), and the recommendation of both WHO Expert Committee on Diabetes Mellitus (1980) and Japan Diabetes Society Committee on Diagnosis of Diabetes Mellitus (1982). Furthermore, I discussed perspectively the problems remained to be solved in the future.