Normal fasting blood glucose levels are 3.9-6.1 mmol/l, normal 2-hour postprandial blood glucose levels should be <7.8 mmol/l, and normal random blood glucose should be <11.1 mmol/l. Fasting blood glucose ≥6.1 mmol/l but <7.0 mmol/l and 2-hour post glycemic load blood glucose <7.8 mmol/l suggests impaired fasting glucose. Impaired glucose tolerance is suggested when fasting blood glucose is <7.0 mmol/l but 2-hour post glycemic load blood glucose is ≥7.8 mmol/l and <11.1 mmol/l. Fasting blood glucose refers to at least 8 hours without food preprandial blood glucose, such as fasting, 2 hours after meal blood glucose is higher than normal but does not meet the criteria for the diagnosis of diabetes mellitus, can be preceded by diet, exercise to control blood glucose, if ineffective is recommended to consult a doctor in a timely manner, under the guidance of the doctor oral hypoglycemic drugs and other methods of treatment. Diabetic patients with poor glycemic control are susceptible to a variety of acute and chronic syndromes, such as diabetic ketoacidosis, diabetic peripheral neuropathy, diabetic retinopathy and so on. If the blood glucose exceeds the normal range, you can control the blood glucose through diet and exercise first, if the blood glucose through diet and exercise control is still not up to the standard, then you should immediately go to the hospital, follow the doctor's instructions to use medication, do not change the use of medication arbitrarily.