The diagnosis of diabetes mellitus cannot be confirmed solely on the basis of a fasting blood glucose of 7.7 mmol/L. The diagnosis of diabetes mellitus requires a combination of blood glucose and clinical symptoms. The diagnosis of diabetes mellitus is based on the typical symptoms of “three more and one less” (excessive drinking, excessive urination, excessive eating, and weight loss) coupled with a venous plasma glucose measurement of ≥11.1mmol/L at any time of the day, a fasting blood glucose of ≥7.0mmol/L, or a 2-hour glucose after a glucose tolerance test of ≥11.1mmol/L. If one of these three symptoms is met, the diagnosis of diabetes mellitus can be made. One of them is enough for a diagnosis of diabetes mellitus. Glycated hemoglobin ≥6.5% can be used as an additional diagnostic criterion for diabetes mellitus, but diabetes mellitus cannot be ruled out if it is lower than 6.5%. Patients with fasting blood glucose of 7.7 mmol/L should be seen under the guidance of a medical professional.