Diabetes mellitus--current criteria for laboratory diagnosis.

Among the laboratory methods and test procedures used for the diagnosis of diabetes mellitus in clinical practice, the oral glucose tolerance test, if performed properly, remains the cornerstone in the definitive diagnosis of diabetes. The intravenous glucose tolerance or the tolbutamide response tests may be indicated especially when there is a question of proper oral carbohydrate assimilation. The value of the cortisone-glucose tolerance test is still in question. Insulin assays may be helpful in differentiating between the various types of diabetes. Accepted criteria for normal and abnormal values for all tests are tabulated.