Glycated hemoglobin of 6.3% is generally not normal. Glycated hemoglobin usually reflects the average level of blood glucose in the past two to three months, and the normal value is 4%~6%. Glycated hemoglobin greater than or equal to 6.5% with typical symptoms of diabetes mellitus (e.g., polyuria, polyphagia, polydipsia, weight loss) can be considered diabetes mellitus, and glycated hemoglobin of 6.3% is not normal, but it is not enough to diagnose diabetes mellitus. Glycated hemoglobin of 6.3% should be evaluated by measuring fasting blood glucose and two-hour postprandial blood glucose. There are some factors that can affect the measurement of glycated hemoglobin, such as anemia and erythrocytosis, which may affect the results of glycated hemoglobin measurement. Glycated hemoglobin alone cannot be used as a diagnostic criterion for diabetes mellitus, but can be used as an indicator of satisfactory glycemic control in patients with diabetes mellitus. If abnormal glycosylated hemoglobin is found, please go to the hospital in time to get a clear diagnosis and active treatment to avoid adverse consequences.