Glycated hemoglobin is the product of a non-enzymatic reaction between hemoglobin in red blood cells and glucose in serum. Because of its persistent, slow, and irreversible nature, glycated hemoglobin can effectively reflect the average blood glucose level over the past 2~3 months. The normal range of glycated hemoglobin for a normal person is generally between 4% and 6%. Due to the different testing methods and reagents, the reference indexes are different in different hospitals and need to be analyzed specifically. Glycated hemoglobin value is not easily affected by factors such as eating, hypoglycemic drugs, etc. It can relatively accurately reflect the blood glucose level in the past period of time as a whole, and is often used as one of the indicators of glucose monitoring for diabetic patients in clinic, and can also be identified with other factors causing blood glucose elevation. If abnormal glycosylated hemoglobin occurs, please consult the hospital in time and take active diagnosis and treatment to avoid delaying the condition.