A glycosylated hemoglobin of 6.1% does not confirm a diagnosis of diabetes. The diagnosis of diabetes mellitus is based on the combination of fasting and postprandial blood glucose, as well as the presence or absence of typical symptoms of diabetes such as dry mouth and excessive drinking. 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 venous plasma glucose ≥11.1 mmol/L, fasting blood glucose ≥7.0 mmol/L, or 2-hour glucose ≥11.1 mmol/L after a glucose tolerance test at any time of the day, which can be diagnosed as diabetes mellitus. 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 at less than 6.5%. It is recommended that patients with elevated glycosylated hemoglobin go to the endocrinology department in time to avoid delays.