If the fasting blood glucose is 6.8mmol/l, it is high. If the 2-hour postprandial blood glucose value is 6.8 mmol/l, then it is a normal blood glucose value. If it is found during daily monitoring of fasting blood glucose in a healthy person, then this value is higher than normal, but does not meet the diagnostic criteria for diabetes. Normal fasting blood glucose value is 3.9~6.1mmol/l. Further review is needed to clarify the cause of elevated fasting blood glucose. The diagnostic criteria for diabetes are based on fasting blood glucose, random blood glucose or oral glucose tolerance test (OGTT) 2-hour blood glucose values. Symptoms of diabetes are defined as excessive drinking, urination, eating and unexplained weight loss. Diabetes is diagnosed when diabetic symptoms plus random blood glucose ≥11.1 mmol/l or fasting blood glucose ≥7.0 mmol/l or OGTT 2-hour blood glucose ≥11.1 mmol/. Different times of blood glucose monitoring and the presence or absence of eating affect the clinical judgment and should be analyzed on a case-by-case basis.