There are two types of blood glucose units, the first is mmol/L, a dosage unit usually used in China, and the second blood glucose unit is mg/dL. there is a formula between the two, 1mmol/L = 18mg/dL. so it depends on the specific unit to understand the blood glucose status. The currently used diagnostic criteria for diabetes use mmol/L as the basic unit. For example, fasting plasma glucose level ≥7.0mmol/L, 2h plasma glucose level ≥11.1mmol/L in 75g glucose tolerance test, random intravenous plasma glucose level ≥11.1mmol/L, the unit used is mmol/L, but it can also be correspondingly converted to mg/dL, which is multiplied by the factor of 18. It is also important to know the value of hypoglycemia, which is to be considered if the blood glucose is <3.9 mmol/L in diabetic patients and <2.8 mmol/L in normal people. Therefore, when testing blood glucose and as a diagnostic criterion, the unit of blood glucose is very important, and the wrong unit will affect the judgment of the specific value of blood glucose. In our daily life, we should pay attention to the high or low blood sugar. High blood glucose is likely to induce acute complications or chronic complications in patients with long duration of disease, while low blood glucose is also likely to lead to some adverse events. Therefore, it is very important to monitor blood glucose well, and for people with high risk factors related to high blood glucose, it is important to do blood glucose screening in general.