Fasting is required to check blood glucose and lipids. Fasting means no caloric intake for 8 hours. Patients are usually instructed to eat normally the day before and avoid eating from 8:00 p.m. until the next day’s blood draw, when the blood sample is collected and called fasting blood. The fasting blood sample is called fasting blood. It can be checked for fasting blood glucose, blood lipids, liver and kidney functions, etc. Patients should pay attention to the following points during the process of blood sampling for blood glucose and lipids: 1. Eat normally the day before the test, don’t eat too much or too little, especially carbohydrates, if you eat too little, the test results of the next day will be inaccurate; 2. Avoid eating too greasy food, otherwise blood lipids will easily change the next day; 3. Avoid too much exercise, heavy physical labor, mood swings, which can affect the blood glucose and 4, after the fasting starts, when the patient is thirsty and needs to drink water, or when he wants to take some medicine early in the morning, he must use plain water, not drinks or water with sugar, to avoid inaccurate fasting blood sugar; 5, in the process of blood sugar measurement, the patient needs to measure fasting blood sugar, but also pay attention to measuring the 2-hour postprandial blood sugar, because a large part of our morbid population has normal fasting blood sugar and elevated postprandial blood sugar. If only fasting blood glucose is checked, but not 2 hours postprandial blood glucose, it is easy to cause missed diagnosis and misdiagnosis.