What it is
Liver function tests, sometimes called a liver panel or LFTs, are blood tests that measure certain enzymes, proteins and other substances made or processed by the liver. Common items on a panel include enzymes often abbreviated ALT and AST, as well as alkaline phosphatase, bilirubin and albumin.
Some of these markers can rise when liver cells are irritated or inflamed. Others reflect how well the liver is making proteins or clearing waste. Despite the name, the tests do not directly measure every liver job, so many clinicians think of them as a helpful signal rather than a complete picture.
An unusual result does not point to one cause. Viral hepatitis (such as hepatitis A, B or C), medications, alcohol, fatty liver, bile duct issues and many other things can all affect results. Only a licensed clinician can interpret your numbers in the context of your health history.
How it’s traditionally been approached
Liver function tests have long been used as a first-look tool. They are commonly ordered as part of general checkups, before or during certain medications, and when someone has symptoms or risk factors that raise questions about the liver.
When results are outside the usual range, clinicians have traditionally looked at the pattern, repeated the tests over time, and considered the person's history. Additional blood tests, including screening for hepatitis B and hepatitis C, imaging or other evaluations may be discussed.
Hepatitis A is generally acute and self-limited, while hepatitis B and C can become chronic infections. Hepatitis C can often be treated and cleared with modern antiviral medication, and hepatitis B is effectively managed with antiviral therapy and monitoring. Whether any of this applies to you is something a clinician decides after an evaluation.
How the right doctor may help
The right doctor, such as a primary care clinician or a liver specialist, may help you understand what your results mean for you. A visit generally includes questions about your health history, medications and supplements, alcohol use, family history and any symptoms, and may include a physical exam.
Your provider may explain which numbers were outside the usual range, whether repeat testing makes sense, and whether other tests are worth discussing. They may also talk with you about hepatitis screening and vaccination, which are conversations to have with a licensed clinician rather than steps to take on your own.
Helpful questions to ask: What do my results suggest, and what might explain them? Should the tests be repeated? Could any of my medications or supplements play a role? Do I have risk factors that make hepatitis screening worth discussing? What follow-up, if any, makes sense? You can find independent licensed providers through Providers.plus.
The whole-person view
Body, mind and stress affect each other. Waiting on lab results or learning that a number is unusual can bring worry, and ongoing stress can influence sleep, eating, and daily habits that are part of overall well-being. Looking at the whole person is a reasonable way to think about health.
If worry or tension feels heavy, some people explore body-based support such as Somatic Experiences, while others find talk therapy through Therapists.plus helpful. These can complement, not replace, the care of a licensed medical professional.
Keep in mind
- This page is educational only and is not medical advice, a diagnosis, or a substitute for an evaluation by a licensed clinician.
- Liver function test results need professional interpretation; a result outside the usual range does not by itself mean a particular condition, and a result within range does not rule out every concern.
- Do not start, stop or change any medication or supplement based on this page; ask a licensed provider.
- This site is not for emergencies. For confusion, severe abdominal pain, vomiting blood, or significant yellowing of the skin or eyes with fever, call 911. In a crisis, call or text 988.
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Frequently asked questions
What are liver function tests?
Liver function tests are blood tests that measure enzymes, proteins and other substances related to the liver. A licensed clinician uses them as one piece of information about liver health. They are often grouped together as a liver panel.
What do liver function tests check for?
They look at markers that may reflect liver cell irritation, bile flow and the liver's ability to make proteins. They do not diagnose a specific condition on their own. A clinician considers them alongside your history, symptoms and other tests.
Can liver function tests detect hepatitis?
They can show signs that the liver may be inflamed, but they cannot tell which type of hepatitis, if any, is involved. Specific blood tests for hepatitis A, B and C are used for that purpose. Ask a licensed clinician whether screening makes sense for you.
What does it mean if my liver function tests are high?
A high result can have many possible causes, including viral infections, medications, alcohol, fatty liver and others. Some are temporary and some need follow-up. A licensed provider can interpret your results and decide whether repeat or additional testing is appropriate.
Do I need to fast before liver function tests?
Instructions vary depending on what else is being tested, so it is best to follow what your provider or lab tells you. Some panels are done without special preparation, while others ask for fasting. Check with the office that ordered your test.
Is hepatitis treatment available if my tests show a problem?
Hepatitis treatment depends on the type and on a clinician's evaluation. Hepatitis A is generally acute and self-limited, hepatitis C can often be treated and cleared with modern antiviral medication, and hepatitis B is effectively managed with antiviral therapy and monitoring. A licensed provider decides what is appropriate for you.
Educational resource. Hep Programs shares general information and connects people with independent doctors. It is not medical advice, diagnosis or treatment. Talk with a licensed professional about your health.