The common symptoms of hyperglycemia are three more and one less, i.e., drinking more, eating more, urinating more and losing weight, which are typical symptoms of diabetes. However, for the elderly, most of them do not have typical symptoms, and many of them are found by accident through hospitalization or physical examination. The main manifestation of hyperglycemia in the elderly is the increase of blood sugar two hours after meals. There are also elderly people who find the increase of blood sugar accidentally through complications. For example, elderly people were found to have higher than normal blood glucose through hospitalization and finally diagnosed with diabetes. And some elderly people are found to have diabetes because of unexplained wasting, blurred vision, numbness of hands and feet, and incurable skin infections. Therefore, for the elderly, those who are in a position to do so need to routinely have fasting blood glucose, two-hour postprandial blood glucose and glycated hemoglobin tests to detect early whether they have diabetes and need early detection and treatment.