Blood glucose monitoring is an important part of comprehensive diabetes management, and self-monitoring is now a key measure for assessing blood glucose levels. The times chosen for blood glucose monitoring are usually before three meals, two hours after three meals, at bedtime and at night. Blood glucose monitoring at multiple times is important for controlling diabetes and preventing chronic complications. I. The significance of monitoring fasting blood glucose The American Diabetes Association (ADA) uses fasting blood glucose as a selective diagnostic criterion for diabetes, rather than the 2-hour postprandial blood glucose of the oral glucose tolerance test (OGTT). Because postprandial blood glucose may be affected by a variety of factors, fasting blood glucose is more stable and more repeatable than postprandial blood glucose. Fasting blood glucose, as the starting point of blood glucose changes during the day, is closely related to postprandial blood glucose. Fasting blood glucose is a predictor of postprandial blood glucose level. Therefore, whether it is blood glucose monitoring or blood glucose control, it should start from fasting blood glucose. The significance of monitoring postprandial blood glucose In 2005, the Chinese heart survey found that most of the Chinese coronary heart disease inpatients combined with abnormal glucose metabolism, if no glucose tolerance test is conducted, only relying on the detection of fasting blood glucose, 87.4% of abnormal glucose regulation and 80% of diabetic patients will be missed. Moreover, most of the elderly glucose patients who do not have the symptoms of “three more and one less” only show postprandial hyperglycemia. Therefore, monitoring postprandial blood glucose can understand the control of blood glucose on the one hand, and has certain significance for the prevention of cardiovascular and cerebrovascular diseases on the other hand. Third, the monitoring program should be different from person to person. When the medication is just started, the blood sugar should be measured 7 times a day, namely before three meals, 2 hours after three meals and before going to bed. If necessary, the blood glucose at 2~3 am should also be measured. In this way, the patient and the doctor can have a more comprehensive understanding of the blood glucose control situation, so that they can make targeted adjustments to the treatment plan and make the blood glucose come down and remain stable as soon as possible. When the blood glucose is stable, for those who receive insulin therapy, it is recommended to self-measure blood glucose at least 3 times a day, and the monitoring frequency for non-insulin therapy patients should be adapted to the treatment plan and the need to achieve the control goal. It can be measured 4 times a day, i.e. fasting (before breakfast), 2 hours after 3 meals, and only 1~2 days a week. If blood glucose remains stable, some patients may only need to be measured once every two weeks. In addition, in case of infections, addition or reduction of medications and patients with high blood sugar fluctuations (when there are frequent hypoglycemia or hyperglycemia), the number of blood sugar measurements should be increased appropriately.