Liver function blood test without water, but can gargle. Liver function phlebotomy is to detect the concentration of alanine aminotransferase related components within the blood, through these indicators, it is possible to understand whether the liver is damaged, as well as the severity of the damage, and drinking or eating will dilute the blood, affecting the concentration of the test items in the blood, which will have a certain negative impact on the results of the test, leading to bias in the results, therefore, fasting is required before the liver function phlebotomy test. Although you are not allowed to drink water before the test, gargling will not dilute the blood and will not affect the accuracy of the test results, so it is possible to gargle before the blood test. Fasting means no food or water for 8 to 12 hours. Patients should have an empty stomach before undergoing liver function blood tests, and please consult your physician if there are any special circumstances.