Oral Glucose Tolerance Test (OGTT) refers to giving a patient 75g of glucose orally and then measuring the change in blood glucose to observe the patient’s ability to tolerate glucose, which is currently recognized as the gold standard for the diagnosis of diabetes. Oral Glucose Tolerance Test (OGTT) is to give a patient 75g of glucose orally and then measure the change of blood glucose to observe the patient’s ability to tolerate glucose. After a normal person takes glucose orally, it is rapidly absorbed into the blood by the gastrointestinal tract, and the blood glucose value reaches a peak in 30-60 minutes, but generally does not exceed 8.9mmol/l (160mg/l). This is due to the rapid increase of blood glucose stimulating insulin secretion, which causes blood glucose to drop rapidly, and blood glucose approaches normal at 2 hours and returns to fasting normal level at 3 hours. Unlike diabetic patients, it is always a peak value and lasts for too long. Precautions for oral glucose tolerance test: 1. Non-stressed state. 2, 3 days before the test daily intake of sufficient carbohydrate 200 grams or more. 3, normal gastrointestinal function and fasting for at least 10 hours. Quit smoking. 4, should not be absolutely bedridden, and should not be strenuous exercise. 5.Be sure to do it in the morning. Exclude the influence of drugs (such as birth control pills, diuretics, phenytoin sodium).