A two-hour postprandial blood glucose of 7.9 mmol/L is slightly high, and it is recommended to consult a doctor to determine the cause of the high blood glucose. The two-hour postprandial blood glucose concentration test requires the patient to calculate the blood glucose concentration two hours after the first bite of food, and its normal range should be less than 7.8mmol/L. The normal range is 7.8~11.1mmol/L while the fasting blood glucose is 7.8~11.1mmol/L. A two-hour postprandial blood glucose of 7.8~11.1mmol/L with normal fasting blood glucose is considered abnormal glucose tolerance; a blood glucose level greater than or equal to 11.1mmol/L meets one of the criteria for the diagnosis of diabetes mellitus. It is recommended to go to the hospital and ask the doctor to make a judgment if the two-hour postprandial blood glucose value is abnormal.