The blood glucose two and a half hours after meal (i.e. 2.5 hours) is not inaccurate, only the name and reference value are different, and it cannot be measured according to the blood glucose value 2 hours after meal. The blood glucose in this time period belongs to random blood glucose, and the value cannot exceed 11.1mmol/L. If it exceeds 11.1mmol/L, the patient should go to test fasting blood glucose, 2 hours after meal blood glucose and glycated hemoglobin to determine whether he has diabetes. The 2.5 hours after meal is usually not called postprandial blood glucose, and the general sense of postprandial blood glucose refers to the 2 hours after meal blood glucose. Normal people have fasting blood glucose of 3.9-6.1mmol/L and 2 hours after meal blood glucose value <7.8mmol/L. If fasting blood glucose is ≥7.0mmol/L and 2 hours after meal blood glucose is ≥11.1mmol/L, it is important to consider whether diabetes has occurred. Diabetes can also be diagnosed if there is only 1 fasting blood glucose ≥7.0mmol/L, along with unexplained weight loss. Generally in the process of testing blood glucose in diabetic patients, the better the blood glucose control, the less frequent the test; the worse the blood glucose control and the occurrence of hyperglycemia, the more frequent the test needs to be. It is important to try to control blood sugar within a relatively normal range to reduce the appearance of various chronic and acute complications.