Postprandial blood glucose generally refers to the concentration of blood glucose two hours after a meal, and a two-hour postprandial blood glucose of 4.2mmol/L is normal. Clinically, two-hour postprandial blood glucose concentration is often used to determine the patient’s blood glucose level, which can reflect the body’s sensitivity to insulin and insulin secretion to a certain extent, generally refers to the blood glucose concentration two hours after the beginning of the calculation from the beginning of the meal, and the normal value should be less than 7.8 mmol/L, so postprandial blood glucose of 4.2 mmol/L belongs to the normal situation. If the two-hour postprandial blood glucose is greater than or equal to 11.1mmol/L and there are typical symptoms of diabetes, the diagnostic standard of diabetes has been reached. If the two-hour postprandial blood glucose value is abnormal, it is recommended to go to the hospital.