Some people have diabetes even though their fasting blood sugar is normal, and two or three years after they have the disease, their fasting blood sugar is still normal. We say that fasting glucose is an indicator in the diagnosis of diabetes, but based on this one indicator alone, about one-third of diabetes will be missed. At present, the indicator for monitoring blood sugar in most physical examination programs is fasting blood sugar, and if fasting blood sugar is normal, the examinee is usually mostly told that there is no problem with blood sugar and that it is not diabetic. What actually is it? Normal fasting blood sugar may not be without diabetes. Generally there are three standard points for clinical diagnosis of diabetes: 1, blood sugar is greater than 7mmol/L when fasting; 2, blood sugar is greater than 11.1mmol/L 2 hours after meal or glucose tolerance test; 3, whether or not meal any moment detection is greater than 11.1mmol/L. As long as these conditions are met, more than two times of examination, are diagnostic of diabetes. Even if the fasting blood sugar is normal, we cannot exclude that it is not diabetes. If it belongs to the high-risk group, such as parents with diabetes, further examination should be recommended. Diabetes can be diagnosed when fasting blood sugar exceeds 7 mmol/L or postprandial blood sugar is greater than 11.1 mol/L. Glucose tolerance tests, and glycated hemoglobin tests, are helpful in identifying more diabetic patients.