Liver function tests are blood tests used to help diagnose and monitor liver disease or damage. The tests measure the levels of certain enzymes and proteins in your blood.
Some of these tests measure how well the liver is performing its normal functions of producing protein and clearing bilirubin, a blood waste product. Other liver function tests measure enzymes that liver cells release in response to damage or disease.
Abnormal liver function test results don't always indicate liver disease. Your doctor will explain your results and what they mean.
Liver function tests can be used to:
Liver function tests check the levels of certain enzymes and proteins in your blood. Levels that are higher or lower than normal can indicate liver problems. Some common liver function tests include:
The blood sample for liver function tests is usually taken from a vein in your arm. The main risk associated with blood tests is soreness or bruising at the site of the blood draw. Most people don't have serious reactions to having blood drawn.
Certain foods and medications can affect the results of your liver function tests. Your doctor will probably ask you to avoid eating food and taking some medications before your blood is drawn.
The blood sample for liver function tests is usually drawn through a small needle inserted into a vein in the bend of your arm. The needle is attached to a small tube, to collect your blood. You may feel a quick pain as the needle is inserted into your arm and experience some short-term discomfort at the site after the needle is removed.
Your blood will be sent to a laboratory for analysis. If the lab analysis is done on-site, you could have your test results within hours. If your doctor sends your blood to an off-site laboratory, you may receive the results within several days.
Normal blood test results for typical liver function tests include:
These results are typical for adult men. Normal results vary from laboratory to laboratory and might be slightly different for women and children.
Your doctor will use these results to help diagnose your condition or determine treatment you might need. If you already have liver disease, liver function tests can help determine how your disease is progressing and if you're responding to treatment.