The product of the combination of hemoglobin and blood glucose in red blood cells in human blood is glycated hemoglobin. The combination of blood glucose and hemoglobin to produce glycated hemoglobin is an irreversible reaction and is directly proportional to the concentration of blood glucose, and the test for glycated hemoglobin usually reflects the patient’s blood glucose control in the last 8 to 12 weeks. Therefore the measure of the level of diabetes control is glycosylated hemoglobin. Glycated hemoglobin and blood glucose control: 4%-6% indicates normal blood glucose control, 6%-7% indicates satisfactory blood glucose control, 7%-8% indicates fair blood glucose control, 8%-9% indicates unsatisfactory blood glucose control, need to strengthen blood glucose control, pay more attention to diet and exercise, and adjust the treatment plan under the guidance of the doctor. >9% indicates poor glycemic control, which is a risk factor for the development of chronic complications and may lead to diabetic nephropathy, atherosclerosis, cataracts and other complications, and may lead to ketoacidosis and other acute complications.