Does this test have other names?

Liver function test (LFT); hepatic function test; liver function panel (LFP)

What is this test?

This group of tests measures specific proteins and enzymes in your blood.

Your liver is the second-largest organ in your body. It converts the food you eat into energy and nutrients and filters waste from your blood.

A liver panel checks the health of your liver and can help diagnose liver damage or disease. The panel often includes these tests:

• Albumin. Albumin is a protein made in the liver.

• Alkaline phosphatase (ALP). ALP is an enzyme found in high quantities in your liver, bile duct, and elsewhere in your body.

• Alanine transaminase (ALT). ALT is another enzyme found in your liver.

• Aspartate transaminase (AST). AST is another enzyme found in your liver, heart, and muscles.

• Total protein. Total protein measures the amount of protein in your blood. Globulin and albumin are the two main proteins found in the blood.

Liver panel or liver function tests also measure bilirubin, a waste product that forms when red blood cells break down. This test measures total bilirubin and direct bilirubin. Total bilirubin is the amount of bilirubin in your blood. Direct bilirubin measures the bilirubin that is made in your liver.

Why do I need this test?

You may need this test as part of a routine checkup. You may also have this test if you have symptoms of liver disease or damage. Symptoms include:

• Yellow color of your skin and the whites of your eyes (jaundice)

• Dark-yellow colored urine

• Gray or clay-colored or black and bloody bowel movements

• Nausea or vomiting

• Diarrhea

• Loss of appetite

• Belly swelling or pain

• Weight loss or gain

• Fatigue

You also might have this test if you've been exposed to a hepatitis virus, have a family history of liver disease, drink excessive amounts of alcohol, or take medicines that can cause liver damage.

You may also need this test to help your healthcare provider watch the progression of a virus like hepatitis that affects the liver or liver damage caused by alcohol.

What other tests might I have along with this test?

Your healthcare provider may also order these tests:

• Gamma-glutamyl transpeptidase (GGT). GGT is another enzyme found in large amounts in your liver, bile ducts, and pancreas.

• Prothrombin time. Prothrombin is protein made in your liver. It helps blood to clot. A prothrombin time test measures how long it takes your blood to clot.

What do my test results mean?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

Normal ranges for liver function tests vary depending on various factors, including your age and gender.

Results are given in grams per deciliter (g/dL), milligrams per deciliter (mg/dL), units per liter (U/L), or international units per liter (IU/L). Here is an example of what is tested:

• Albumin

• Total bilirubin

• Direct bilirubin

• ALP

• ALT

• AST

• Total protein

High levels of these proteins and enzymes may mean that your liver or bile duct is damaged or diseased. Overall, a pattern of abnormalities among the results may be more significant than the individual test results. Levels of ALT are useful for finding out whether you have hepatitis.

Diseases unrelated to the liver can cause abnormal test results. Some people with advanced liver disease may have normal test results.

How is this test done?

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.

What might affect my test results?

Your results can be affected by:

• Viruses

• How much alcohol you drink

• Certain medicines

• Obesity

How do I get ready for this test?

You don't need to prepare for this test. But the test may be more accurate if you fast for 10 to 12 hours beforehand. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you take. This includes medicines that don't need a prescription and any illegal drugs you may use.