The test for glucose tolerance usually refers to the oral glucose tolerance test (OGTT test). OGTT test is to measure fasting venous blood glucose after 8 to 10 hours of fasting, then adults take 75 grams of anhydrous glucose orally, dissolved in 250-300 ml of water, and finish it within 5 minutes, the first sip of sugar water starts timing, and then blood is drawn once in the following 30 minutes, one hour, two hours, and three hours to test blood glucose. When blood glucose is higher than the normal range and does not meet the diagnostic criteria for diabetes, an OGTT test can be performed.The OGTT test is a glucose loading test to understand the function of pancreatic β-cells and the body’s ability to regulate blood glucose, and it is an important indicator for confirming the diagnosis of diabetes, and it can also help in the determination of type 1 and type 2 diabetes. Intravenous glucose tolerance test can be used after gastrointestinal surgery or gastrointestinal digestive and absorption disorders, when oral glucose is not suitable. cortisone OGTT test can be used for those with normal OGTT but with a family history of diabetes. Glucose tolerance test should be conducted under the guidance of a doctor, and any abnormality should be promptly consulted and treated under the guidance of a doctor.