1. Fasting blood glucose refers to the blood glucose measured by blood collected before breakfast after overnight fasting for more than 8 hours. Blood glucose measured before midday and dinner. 2.Pre-meal blood glucose refers to the blood glucose measured before breakfast, lunch and dinner. 3.2 hours postprandial blood glucose refers to the blood glucose measured 2 hours after the first bite of breakfast, lunch and dinner. 4.Random blood glucose The blood glucose measured at any other time of the day, such as before bedtime, midnight, etc. Usually when your blood sugar is often high recently, you should monitor fasting and 2 hours after meal blood sugar, which can more accurately reflect the degree of your elevated blood sugar. When your blood sugar has been low recently, it is better to monitor your preprandial blood sugar and nighttime blood sugar. It is better to monitor blood glucose at different times of the day than at the same time of the day. The former is more likely to reflect the pattern of blood glucose changes during the 24 hours of the day, while if blood glucose is measured at the same time every day, you will not always know how well your blood glucose level is controlled during the rest of the day. For patients with more stable blood glucose control, the interval of blood glucose monitoring can be longer, 1 week 2 weeks or longer. However, for patients whose blood glucose has fluctuated a lot recently, the frequency of monitoring should be increased according to their condition.