Whenever the sugar is measured is accurate, because the standard value of blood sugar measured at different times is different. Generally speaking, for non-diabetic patients, the recommended time to check blood sugar is the blood sugar before morning and two hours after breakfast, which is mainly used for the diagnosis of diabetes. For diabetic patients, the time of blood glucose measurement is naturally different for different conditions. For example, for pre-meal glucose monitoring, when the blood glucose level is high, the fasting blood glucose level is the first thing to pay attention to. Patients who inject insulin, especially those who inject medium and long-acting insulin; in addition, before, during and after exercise as well as when changing hypoglycemic drugs, we should test our blood glucose more often, especially when there are symptoms of hypoglycemia with panic and cold sweat, we need to monitor blood glucose accurately in order to correct hypoglycemia in time. Therefore, as long as the blood glucose meter is accurate, whenever the blood glucose is measured is accurate, and blood glucose should be monitored diligently, especially for diabetic patients.