1, liver function test must be fasting before, check the liver function to go to the hospital in the morning to draw blood, so the test needs to fast before do not eat, forbidden breakfast, so as not to affect the liver function results. 2, before the liver function test, pay attention to rest, ensure sleep, do not make strenuous exercise, and do not drink alcohol. Because strenuous exercise and drinking can affect the normal value of transaminases. 3, before the liver function test some drugs can not be taken, such as taking vitamin D, atipine and other drugs will affect the determination of jaundice index; taking drugs containing opiates can lead to an increase in transaminase activity and affect the accuracy of liver function test.