In some patients with positive urine glucose and normal or slightly higher than normal fasting glucose, or normal fasting glucose and increased postprandial glucose in the boundary state, in order to clarify whether it is diabetes, it is necessary to do glucose tolerance test (OGTT) to clarify the diagnosis, especially for those who have a clear family history of diabetes, it is more necessary to do this test. Tang Xiangyu, Department of Endocrinology, Guangdong Province Hospital of Traditional Chinese Medicine The following are the main points to note when doing the glucose tolerance test: ① Eat at least 150 grams of carbohydrates daily for three days before the test. Smoking, drinking tea, wine and coffee are prohibited before and during the test. ② must fast for more than 8 hours before the test, but should not exceed 16 hours, you can drink water, the test at 7 ~ 9 am. ③The test will be 75 grams of glucose powder dissolved in 300mL of warm boiled water, to be taken within 5 minutes. Start timing from the first sip of sugar water. Blood will be collected punctually 1, 2 and 3 hours after fasting and sugar respectively, where the 2-hour blood glucose collection time point requires the error before and after not more than 3 minutes. ④Disease and trauma, such as fever, acute cardiovascular and cerebrovascular disease, etc., put the body in a state of stress, which may temporarily increase blood glucose and reduce glucose tolerance, and this test should be done when the body resumes normal activities after recovery. ⑤ Children’s glucose load is calculated as 1.75g/kg body weight, but not more than 75g. The diagnostic criteria for diabetes mellitus are the same as those for adults. ⑥In general, when diagnosing diabetes, it is appropriate to use venous plasma to detect blood glucose concentration by conventional biochemical method. Detection of capillary glucose concentration by blood glucose monitor is mainly used to monitor blood glucose changes and is not used as a basis for diagnosis. Indications for diabetes screening for asymptomatic undiagnosed people: 1. Age >45 years, if fasting blood glucose ≥5.6mmol/L or random blood glucose ≥6.5mmol/L need to do further glucose tolerance test (OGTT). If normal, recheck every 2-3 years. 2. Screening every 1 year for those aged <45 years with the following conditions < p=""> ① Obesity ≥ 20% of standard weight, or body mass index (BMI) (kg/m2) ≥ 25 for men and ≥ 24 for women. ② History of diabetes in first-degree relatives. ③History of delivery of a huge baby (≥4.0kg) or history of gestational diabetes mellitus ever diagnosed. ④Blood pressure ≥ 140/90 mmHg. ⑤HDL–C ≤ 0.9 mmol/L and/or triglycerides ≥ 2.2 mmol/L. ⑥Previous screening with IFG or IGT.