Blood sampling for liver and kidney function tests requires fasting because liver and kidney function tests are biochemical tests that include liver function and kidney function tests, indicators of liver function, such as albumin, total protein, globulin, albumin ratio, etc., as well as indicators of liver cell damage. Kidney function tests include glomerular filtration rate, such as blood endogenous creatinine clearance, blood creatinine measurement, and blood urea nitrogen measurement. After fasting or fasting for 8 hours at 8 pm the day before the re-examination, the specimen is collected on an empty stomach the next morning, which is a method of fasting blood collection, that is, a blood collection is done in the morning when you wake up in the morning, before breakfast, mainly for biochemical tests. The advantage is that it can avoid the influence of dietary components and physiological activities during the day on the test results, and because the blood is collected at a fixed time each time, it is also easy to compare before and after. In addition to fasting blood collection, according to the different laboratory items, to do the necessary to take time regulations, such as some are specific time blood collection, such as hormone, glucose determination, are specified time, such as glucose determination has fasting blood glucose determination, and OGTT, called glucose tolerance test, there are provisions for half an hour after meals, 1 hour, 2 hours, 3 hours to do the determination, there are clear time regulations. For emergency blood collection, blood collection is not affected by time, and the checklist clearly indicates the time of emergency and blood collection.