For checking blood lipids and fasting blood sugar, fasting is required. Drinking and eating will affect the accuracy of the results, while fasting is not required if testing postprandial blood sugar or random blood sugar. Lipid test mainly contains total cholesterol, triglyceride, LDL cholesterol, HDL cholesterol and so on, of which total cholesterol and triglyceride, to a certain extent, will be interfered by food. Blood glucose check has fasting blood glucose and postprandial blood glucose, and the influence of diet on blood glucose is very clear. Therefore, both lipid and fasting blood sugar checks should be done on an empty stomach. Generally speaking, it is required to fast for 8-12 hours, that is, try not to eat any food or drink water after 10 p.m. the night before the test, and have blood tests drawn around 6-8 a.m. the next morning. Laboratory tests should be performed under the supervision of a doctor.