Common tests for diabetes mellitus include fasting blood glucose measurement, 2-hour postprandial blood glucose measurement, urine glucose measurement, oral glucose tolerance test, glycosylated hemoglobin measurement, insulin and C-peptide release test, and so on. 1. Fasting blood glucose and 2-hour postprandial blood glucose: clinically, fasting blood glucose and 2-hour postprandial blood glucose are mostly used as assessment indicators, which can be detected by fingertip blood or venous blood. 2. Urine glucose: urine glucose measurement is usually a routine urine test, positive only indicates that the blood glucose exceeds the renal glucose threshold, negative can not exclude diabetes. 3. Oral Glucose Tolerance Test: This test is generally recommended when blood glucose is higher than normal but does not meet the diagnostic criteria for diabetes mellitus. The examiner fasts for 8 to 10 hours the night before, measures fasting blood glucose early in the morning of the next day, and then drinks sugar water and determines the blood glucose after 0.5 hours, 1 hour, 2 hours and 3 hours respectively. 4. Glycated hemoglobin measurement: reflecting the patient’s average blood glucose level in the last 8~12 weeks, it is a more stable test to assess the effect of long-term blood glucose control. 5. Insulin and C-peptide release test: It can assess the function of pancreatic islets by measuring the fasting plasma insulin and C-peptide values as well as the test values after taking sugar water. It is recommended that patients should seek medical advice in time and choose the appropriate test under the guidance of the doctor.