Diabetes: diagnosis and classification

Abstract

Diabetes may present with severe thirst, increased urine volume, rapid weight loss, and sometimes coma. Blood glucose concentration is grossly elevated. Glucose will be excreted in the urine, usually in large amounts. In this situation diagnosis is simply confirmed from blood glucose estimation without formal provocative tests. Random plasma glucose concentrations exceeding 2 g/I are diagnostic. The presence of specific microvascular disease, usually retinopathy, also establishes the diagnosis. When such symptoms and signs are absent and blood glucose levels less markedly elevated, measurements made under standard conditions, such as fasting or after a carbohydrate challenge, may be necessary to confirm or refute the diagnosis. Commonly the o~ral glucose tolerance test is performed. The importance of this testas a clinical diagnostic tool has been grossly overemphasized. It is useful only in clearly defined situations.