Diabetes mellitus is a chronic metabolic disease with elevated blood glucose as the main cause, involving all systems of the body and producing a variety of clinical manifestations. To determine whether you are diabetic or not, you can pay attention to the following points: First, there are no symptoms of diabetes, such as unexplained wasting, thirst, blurred vision, numbness of both lower limbs, pins and needles, poor wound healing and other symptoms. Second, you can go to the hospital to check fasting blood sugar, 2-hour postprandial blood sugar and glycosylated hemoglobin, fasting blood sugar, 2-hour postprandial blood sugar and glycosylated hemoglobin are in the normal range, basically you can exclude diabetes. If fasting blood sugar is more than 7.0mmol/L, 2 hours after meal blood sugar is more than 11.1mmol/L and glycosylated hemoglobin is more than 6.5%, the possibility of diabetes is very high. Third, if necessary, oral glucose tolerance test can be done, which means taking 75g of glucose orally and measuring blood glucose 1 hour and 2 hours after taking glucose, respectively, and insulin can be measured simultaneously to judge the function of pancreatic beta cells. The oral glucose tolerance test is the gold standard for the diagnosis of diabetes.