A fasting blood sugar of 8.3 mmol/L is considered high. Normal values for fasting blood glucose should be between 3.9 and 6.1 mmol/L. The diagnostic criteria for diabetes mellitus is a fasting venous blood glucose level ≥ 7.0 mmol/L. If the patient has a fasting blood glucose of 8.3 mmol/L and has typical diabetic symptoms (meaning irritable thirst, excessive drinking, excessive urination, and unexplained weight loss), it is necessary to pay attention to whether he/she is suffering from diabetes, and if he/she does not have typical diabetic symptoms, he/she needs to review his/her blood glucose at a later date. In the case of fingertip blood glucose measured at home, it is recommended to seek medical attention for oral glucose tolerance test and glycated hemoglobin measurement for a definitive diagnosis. After diagnosis of diabetes mellitus, diet and exercise should be actively intervened, and medication to lower glucose should be administered as prescribed by the doctor if necessary.