Elevated glycosylated hemoglobin may be caused by poor blood sugar control, blood system diseases, etc. Consultation with a doctor is recommended. 1. Poor blood sugar control: The most important reason for elevated glycosylated hemoglobin is that the patient’s blood sugar has not been under control for a long time. Glycated hemoglobin reflects the average blood glucose level in the last 2 to 3 months and can be used for monitoring the control of blood glucose level. 2. Blood system diseases: If the survival time of red blood cells is prolonged, it will also cause the increase of glycosylated hemoglobin, such as after splenectomy. In conclusion, when the glycosylated hemoglobin is elevated, it is necessary to consult a doctor in time to clarify the cause of the elevation, and carry out treatment under the doctor’s guidance.