Fasting blood glucose is normal, and postprandial blood glucose 12mmol/L may be diabetes, but only a blood glucose value can not be used as a basis for the diagnosis of diabetes mellitus, need to be combined with the results of glycated hemoglobin, glucose tolerance test and other tests for comprehensive analysis. The latest 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), 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 the glucose tolerance test at any time of the day. A diagnosis of diabetes is made when one of these three is met. Fasting blood glucose is normal and postprandial blood glucose is 12mmol/L. In addition to considering diabetes, it may also be caused by eating too many sweets, infections, stress and other factors, and it is recommended to consult a medical professional for a clear diagnosis and treatment.