Liver Function Tests (Liver Panel)
Reviewed
Also called: LFT, Liver panel, Liver profile, Hepatic function panel
Liver function tests (also called a liver panel) use a sample of your blood to measure several substances made by your liver.
Specimen: Blood
Why this test may be ordered
- Investigating possible liver disease or injury
- Monitoring known liver disease
- Checking for medicine-related effects or risk factors
Preparation and collection
Your provider will tell you how to prepare for your test. You will probably need to fast (not eat or drink) for 10-12 hours before the test. Certain medicines can affect your test results, so be sure to tell your provider about everything you take. But don't stop taking any medicines unless your provider tells you to.
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
Understanding results
Understanding abnormal liver function test results is often complicated. So, it's best to ask your provider to explain what your results say about your health.
- One or more abnormal results: In general, the results of your liver function tests can tell you if: Your liver is inflamed, which means you have hepatitis. You have hepatitis from drinking alcohol or other causes, such as infection. Your liver isn't working well and how weak it has become. You have a problem with your bile ducts. Medicines are harming your liver and how serious the damage is. Limitation: Abnormal results don't always mean you have a problem with your liver. Other conditions can cause high or low levels of certain substances that these tests measure. Next step: So, your provider will also consider your symptoms, medical history, risk for liver disease, and any medicines you take.
- Abnormal results after a recent illness: If you have been ill recently, certain types of abnormal results may be temporary. Limitation: But liver function tests alone usually can't diagnose specific diseases. Next step: In this case, your provider may repeat the tests later to see if your results return to normal.
- ALT, AST, ALP, GGT, bilirubin, albumin, and PT/INR answer different clinical questions.
- Exercise, muscle injury, pregnancy, medicines, alcohol, fasting, and sample quality can alter components.
What to do next
If any of your liver function test results are abnormal, your provider will compare the results of all the substances that were measured. So, if your results are abnormal, you'll usually need other tests to find the exact cause.
- Which reference interval and units apply to my result?
- Could medicines, supplements, illness, or sample timing affect this result?
- Do I need a repeat test or another test before any conclusion is made?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.
U.S. National Library of Medicine: Liver Function Tests (Liver Panel)