Glucose tolerance test is divided into oral glucose tolerance test and intravenous glucose tolerance test, and intravenous glucose tolerance test is mainly used for scientific research. Oral glucose tolerance test practice is as follows: a. Oral glucose tolerance test should be carried out in the early morning after fasting for at least eight hours, and the daily intake of carbohydrates for three days before the test is not less than 150 g. Secondly, 75 g of glucose (if it is glucose powder plus 82.5 g) is added to 250 ml of water to be drunk in five minutes, and the time is counted from serving the first mouthful of glucose-containing liquid, and venous blood for measuring blood glucose and insulin is drawn before, one hour after, and two hours after serving the glucose. One hour before, one hour after sugar consumption and two hours after sugar consumption, venous blood was taken to measure blood glucose and insulin. During the test, subjects should not drink tea, coffee or other sugary drinks, smoke, or do strenuous exercise, but do not need to stay in bed absolutely. The specimen should be sent for examination at an early stage.