The medical name for blood glucose is plasma glucose, and plasma glucose is a very important basis currently used to diagnose diabetes mellitus. The following 3 plasma glucose are usually used as diagnostic criteria for diabetes: 1. Fasting plasma glucose: fasting plasma glucose ≥6.1mmol/L is called elevated blood glucose level; if ≥6.1mmol/L, but <7.0mmol/L, it is called impaired fasting glucose regulation. If it is ≥7.0mmol/L, the diagnosis standard of diabetes is reached; 2. 2h postprandial plasma glucose: usually choose the 2h postprandial glucose among the 75g glucose tolerance test. If the 2h postprandial plasma glucose level is ≥7.8 mmol/L, it is called elevated blood glucose level. If it is ≥7.8 mmol/L but <11.1 mmol/L, it is called abnormal glucose tolerance. If ≥11.1mmol/L, it is called that the diagnostic criteria of diabetes are met; 3. Random venous plasma glucose: if ≥11.1mmol/L, the diagnostic criteria of diabetes have been met. For some special groups of people, it should be noted that the diagnostic criteria may change to some extent. For example, when pregnant women undergo glucose tolerance test screening, usually fasting plasma glucose level ≥ 5.1mmol/L, 1h plasma glucose level ≥ 10.0mmol/L, 2h plasma glucose level ≥ 8.5mmol/L, the diagnostic criteria of gestational diabetes is met. Plasma glucose can be tested at ordinary times to clarify the physical condition, for example, diabetic patients can usually choose fasting glucose status and 2h postprandial glucose status for blood glucose monitoring to know whether the blood glucose control is up to standard. If abnormal blood glucose is present, active lifestyle intervention and, if necessary, medication should be administered, which needs to be done under the guidance of a specialist.