Fasting blood glucose 10.4mmol/L is higher than the upper limit of the normal blood glucose range, may be diabetes, but also other reasons (such as infection, stress, etc.) caused by high blood glucose, diagnosis of diabetes mellitus need to be combined with clinical symptoms to make a comprehensive judgment. The diagnosis of diabetes mellitus is based on the typical symptoms of “three more and one less” (drinking more, urinating more, eating more, and losing weight) plus the measurement of intravenous plasma glucose ≥11.1mmol/L, fasting blood glucose ≥7.0mmol/L, or 2-hour glucose ≥11.1mmol/L after glucose tolerance test at any time of the day, which can be diagnosed as diabetes mellitus if one of them meets the diagnosis. One of them is enough for a diagnosis of diabetes mellitus. The China Type 2 Diabetes 2020 Prevention and Control Guidelines include glycated hemoglobin in the diagnostic criteria, and glycated hemoglobin ≥6.5% can be used as an additional diagnostic criterion for diabetes, but diabetes cannot be ruled out if it is lower than 6.5%. It is recommended that patients with fasting blood glucose of 10.4 mmol/L should go to the endocrinology department of regular hospitals for detailed counseling.