The Oral Glucose Tolerance Test(OGTT)

    The OGTT should be administered in the morning after at least three days of unrestricted diet (greather than 150 g of carbohydrate daily) and usual physical activity. The test should be preceded by an overnight fast of 10-16 hours, during which water may be drunk. Smoking is not permitted during the test. The presence of factors, that influence interpretation of the results of the test must be recorded (e.g. medications, inactivity, infection, etc.).

    After collection of the fasting blood sample, the subject should drink 75 g of glucose in 250-300 ml of water over the course of 5 minutes. Blood samples must be collected 2 hours after the test load.

WHO(1985)

The general agreement was, for epidemiological field survey of adults, that a whole blood or plasma glucose value 2h after a 75-g oral glucose load is the most useful index of glucose tolerance. The 2-h capillary whole blood concentration were normal < 7,8 mmol/l, IGT >=7,8 and <11,1 mmol/l, and DM >=11,1 mmol/l. If patient had previously diagnosed DM we estimated fasting glucose level and confirmed the diagnosis by the medical record or by the data of DM registry in the same district.