The oral glucose tolerance test is the gold standard for diagnosing diabetes, however, there are certain methods and requirements for conducting this test. Oral Glucose Tolerance Test (OGTT) Method 1. Starting at 7-9 a.m., the subject should take 75 g of anhydrous glucose powder dissolved in 300 ml of water or 82.5 g if using 1 molecule of water glucose, or 1.75 g per kg of body weight for children, not to exceed 75 g in total. The test should be completed within 5 minutes. 2. Blood glucose was collected from the forearm before and 2 hours after taking the sugar. 3.During the test, subjects should not drink tea or coffee, smoke or do strenuous exercise, but they should not be absolutely bedridden. 4.Blood specimens should be sent for examination as soon as possible. 5.The daily carbohydrate intake should be at least 150 g within 3 days before the test. 6.Discontinue the use of drugs that may affect OGTT, such as contraceptives, diuretics or phenytoin sodium, for 3-7 days before the test.