Blood glucose reflects the blood glucose level at the time of measurement, and measuring blood glucose is one of the important things that sugar lovers must do almost every day. According to the measurement time, it can be divided into fasting blood sugar, pre-meal blood sugar, post-meal blood sugar and blood sugar at 2~3 am. Blood glucose measurement seems to be a small thing, but there is a lot to learn. 1. Fasting blood glucose: 6~8 o’clock in the morning It is crucial to measure fasting blood glucose at 6~8 o’clock in the morning, and generally speaking, the blood glucose measured at 6~8 o’clock in the morning is the standard fasting blood glucose. At home, it is generally measured at 6~7 o’clock, while the hospital generally opens at 8 o’clock, plus some procedures, it may be measured at 9 o’clock. Even if you don’t eat in the morning, your blood sugar is not constant, but gradually increases. The blood sugar measured at 9:00 is likely to be higher than that measured at 7:00, and the blood sugar measured at 10:00 is higher than that measured at 8:00, causing the illusion that the fasting blood sugar in the hospital is higher than that at home. At this time, the blood glucose measured at home should be used as the standard for blood glucose control. To compare whether the blood glucose measured at home is accurate, it must be measured at the same time, and the blood glucose meter can also be brought to the hospital, and the blood glucose meter can be measured at the same time in the hospital, and if there is a big difference between the two results, it means that the blood glucose meter may not be allowed and needs to be calibrated. 2. Two hours after meal: from the first bite of food Post-meal blood glucose refers to the blood glucose two hours after meal, which is counted from the first bite of food for two hours, not from the end of the meal. Two hours after meal blood glucose is generally the highest blood glucose, and only measuring fasting or pre-meal blood glucose may not fully reflect the control of blood glucose. Pre-meal glucose is mainly to determine whether there is hypoglycemia, and if there are often symptoms of hypoglycemia such as pre-meal panic and hunger, attention should also be paid to monitoring pre-meal glucose. Some insulin users often need to measure the blood sugar at 2~3 am to determine whether insulin can be increased when fasting blood sugar is high, because some fasting hyperglycemia may be due to the rebound of hyperglycemia at night, when insulin not only cannot be increased, but also may need to be reduced. In this case, insulin should not be increased but may need to be reduced. How often is the appropriate time to monitor blood glucose in special cases is also a concern of sugar lovers. Generally speaking, for those who have good blood sugar control, it is enough to measure fasting blood sugar and two-hour postprandial blood sugar every 1-2 weeks or more, while for those who have poor blood sugar control, the number of daily monitoring should be increased, and the number of daily monitoring should be increased to every other day or even several times a day, including bedtime blood sugar. The following cases should be monitored closely (3~7 times a day): when the condition is unstable (such as co-infection or very high blood glucose), when changing medications, people on intensive insulin therapy (patients who inject ≥4 times a day or use insulin pump), and patients with type 1 diabetes.