The range of normal blood sugar: fasting blood sugar is 3.9-6.1mmol/L, and random blood sugar should be <11.1mmol/L. Generally, 3h after meal, blood sugar is already in the normal range, which is fasting level. If patients find elevated blood glucose, it is recommended to go to the hospital in time to improve the glucose tolerance test, except for the case of diabetes. If the patient monitors high blood glucose by himself, but the blood glucose measured in the hospital is not high, there may be an error. In addition, fingertip blood glucose is about 0.6 mmol/L lower than venous blood. Therefore, random blood glucose is generally referred to fingertip blood glucose.