What is it?

Liver function tests check to see how well your liver is working. Some tests measure the amount of certain enzymes in your blood. This can show if the liver is damaged or inflamed.

Other tests measure how well the liver can make certain proteins. Or they show how well the liver removes waste products from the body.

Your doctor will use the test results to help look for conditions such as hepatitis, cirrhosis, or gallbladder problems. Test results that are not normal don't always mean there is a problem with your liver. Your doctor can find out if there is a problem based on your results.

The tests may include:

Alkaline phosphatase (ALP).

This test measures the amount of the enzyme ALP in your blood.

Total protein and albumin.

A total serum protein test measures the amounts of two major groups of proteins in your blood (albumin and globulin). It also shows the total amount of protein. An albumin test measures albumin only.

Bilirubin.

This test measures the amount of bilirubin in your blood. When levels are high, the skin and whites of the eyes may look yellow (jaundice). This may be caused by liver disease.

Alanine aminotransferase (ALT) and aspartate aminotransferase (AST).

These tests measure the amount of the enzymes ALT and AST in your blood.

Why is this test done?

Liver function tests check how well your liver is working. Some tests help show if your liver is damaged or inflamed. Your doctor may order liver function tests if you have symptoms of liver disease. These tests also may be done to see how well a treatment for liver disease is working.

How do you prepare for the test?

In general, there's nothing you have to do before this test, unless your doctor tells you to.

How is the test done?

A health professional uses a needle to take a blood sample, usually from the arm.

What happens after the test?

• You will probably be able to go home right away.
• You can go back to your usual activities right away.