Glycosylated hemoglobin 5.9 is normal. The glycosylated hemoglobin of normal people ranges from 3-6%. Glycosylated hemoglobin reflects the average blood glucose level in the past 8-12 weeks, and it should be noted that its result will be affected by many factors such as the testing method, whether it is accompanied by hematological diseases, and age. Glycosylated hemoglobin cannot reflect instantaneous blood glucose levels, blood glucose fluctuations, or determine whether hypoglycemia has occurred during the process, so it is not a substitute for daily blood glucose monitoring. The normal level of glycosylated hemoglobin only means that the average blood sugar in the past 3 months is okay, but it does not mean that the blood sugar at any point of time is up to the standard, so we must do a good job of daily blood sugar monitoring and recheck glycosylated hemoglobin once every 3 months or so to judge whether the blood sugar control is up to the standard by combining the two.