Blood glucose test does not necessarily require fasting, if you are checking fasting blood glucose, glucose tolerance test, need to fasting; if you are checking random blood glucose, postprandial blood glucose, do not need to fasting. Blood glucose refers to the amount of glucose in the blood, to determine whether the blood glucose test requires fasting, need to be based on the situation, can not be generalized, mainly depends on the purpose of the examination. In general, if the purpose is to check fasting blood glucose as well as glucose tolerance test, the examiner needs to fast and should fast for about 8 hours. If the purpose is to check random blood glucose and postprandial blood glucose, fasting is usually not required. Normally, fasting blood glucose ranges between 3.9 and 6.1 mmol/L, and 2-hour postprandial blood glucose should be <7.8 mmol/L. For diabetic patients, it is recommended that fasting blood glucose be controlled to 7.0 mmol/l or less, and 2-hour postprandial blood glucose to 10.0 mmol/l. If the examiner's blood glucose results are abnormal, further relevant tests should be done to clarify the specific cause.