Fasting blood sugar of 6.58mmol/L is usually not normal and is on the high side. Normal fasting blood glucose range should be 3.9~6.1mmol/L, so fasting blood glucose 6.58mmol/L is high and abnormal, which may be caused by diabetes mellitus, impaired fasting blood glucose (fasting blood glucose is at 6.1~7.0mmol/L but two hours postprandial blood glucose is normal) and other reasons. It is recommended to further improve the oral glucose tolerance test and other tests to determine, if it is impaired fasting glucose, you can through appropriate exercise, dietary management, etc. to reduce blood glucose to within the normal range, if necessary, follow the doctor’s instructions to take medication. If it is caused by diabetes, it can be treated with insulin or oral hypoglycemic drugs such as gliclazide and metformin on the basis of exercise and diet management. If you have abnormal fasting blood glucose values, we recommend you to go to the hospital and ask the doctor to make a judgment based on your own condition, to clarify the cause of the disease and to treat it under the doctor’s guidance.