Fasting blood glucose at 9:30 am may not be as accurate. Fasting blood glucose is the blood glucose concentration measured under the condition of overnight fasting, i.e. keeping at least 8~10 hours without food, the normal range is 3.9~6.1mmol/L, which can effectively reflect the function of pancreatic islet B-cells, and it is also the most common examination index of diabetes mellitus. The best time to measure fasting blood glucose is at 6~8 a.m., and it is not advisable to exercise strenuously or eat breakfast before blood collection. If the measurement time is too late, it may be difficult to truly reflect the patient’s blood glucose value, which may lead to the result being on the high side or on the low side. Patients who need to collect blood for glucose measurement should actively cooperate with the operation process of medical personnel, and if abnormal blood glucose value occurs, it is recommended to go to the hospital for medical treatment.