Glucose screening generally refers to an oral glucose tolerance test, which requires fasting. The oral glucose tolerance test requires fasting after 12:00 p.m. the night before the test, and fasting for 8-10 hours before the test, then fasting blood glucose is drawn for testing, and then blood is drawn to test the glucose level at 0.5 hours, 1 hour, 2 hours, and 3 hours after glucose is consumed, respectively. Therefore, fasting is generally required. In addition, it should be noted that the amount of carbohydrates is not less than 150g per day for 3 days before the test, therefore, it is necessary to eat normally, at least three meals a day, one or two staple foods in each meal. Before the test also need to stop using drugs that may affect the test results such as birth control pills, diuretics, etc. It is recommended to stop for 3-7 days if the condition allows. It is recommended that patients with blood glucose abnormalities seek prompt medical attention and follow the doctor’s instructions.