Consumption of food before blood sampling has no significant effect on routine blood tests and random blood glucose, but it may have some effect on liver and kidney function tests, so it is recommended to keep fasting for at least 8 hours before blood sampling. At present, the results of some common clinical tests such as routine blood tests and random blood glucose tests have lower dietary requirements, so even if some food is consumed before the blood is drawn, it will not affect the test results. However, some tests with high fasting requirements, such as liver function tests, kidney function tests, etc., will lead to errors in the test results if food is consumed, so it is recommended to fast for at least 8 hours before blood sampling for these tests.