Fasting blood glucose testing is required to diagnose diabetes, and it is recommended that blood glucose be checked between 6:00 and 8:00 a.m., before meals. Blood glucose testing is an important test in the diagnosis and treatment process. If used for diabetes diagnosis, it is recommended to draw blood for blood glucose testing between 6:00-8:00 am, before breakfast, and you need to fast for 8-10 hours the night before to ensure the accuracy of the test results. Three days before the blood glucose test, you should get enough sleep, avoid violent mood swings, and avoid taking hormone drugs as much as possible. Give a light diet, avoid eating too sweet food, avoid overeating and avoid drinking alcohol. The postprandial blood glucose test is usually done 2 hours after the meal. Once diabetes is diagnosed, standardized medication should be taken, diet should be strictly controlled, and bad habits should be corrected.