Glycosylated hemoglobin is the product of non-enzymatic catalysis of glucose or other sugars with hemoglobin, reflecting the patient’s blood glucose level averaged over 8 to 12 weeks. Glycated hemoglobin content is positively correlated with blood glucose concentration and consists of HbA1a, HbA1b, and HbA1c, of which HbA1c is the most dominant, and if a patient’s blood glucose is poorly controlled, an elevated HbA1c will occur. In addition, since the life span of blood cells in the blood is about 120 days, HbA1c reflects the patient’s average blood glucose level in the last 8 to 12 weeks. It is important to note that glycated hemoglobin measures the change in blood glucose value over a period of time, not the immediate blood glucose concentration, so factors such as whether or not you are fasting, taking oral hypoglycemic medication, or injecting insulin prior to the measurement will not affect the results. It is recommended that patients with abnormal glycosylated hemoglobin measurements should go to the hospital in a timely manner.