Liver function tests (also called LFTs) are blood tests that can provide information about how your liver is working. They test the levels of a number of proteins and enzymes that are either produced by liver cells or released into the blood when liver cells are damaged.
What is being tested?
The liver is a large organ in the upper right of the abdomen and is necessary for more than 500 functions. Among them, it processes drugs and alcohol, filters toxic chemicals, stores vitamins and minerals, and makes bile, proteins and enzymes.
LFTs examine proteins, enzymes, and other substances that indicate how well your liver is working. They can show if there is damage to liver cells or a blockage to blood flow through the liver.
Why would I need this test?
Doctors often request these tests for people who:
- have liver disease or damage
- are, or might be, infected with hepatitis viruses
- are heavy drinkers
- have a family history of liver disease
- take drugs that can damage the liver
Your doctor might order LFTs if you have:
- dark urine
- weakness or tiredness
- loss of appetite
- nausea and vomiting
- abdominal pain or swelling
How to prepare for this test
No preparation is needed for this test.
Understanding your results
Each of the LFTs gives different information about liver function. The results do not indicate a specific condition, but their combined results can indicate patterns usually seen with liver disease or damage.
If your liver function tests are abnormal, further testing might be necessary to work out what is causing the liver damage and/or disease.
Some LFTs can be affected by conditions in the bones or elsewhere in the body. It is also possible that some LFT results can be mildly abnormal when there is no problem at all.
You should discuss the results with your doctor to see what they mean in your particular situation.
Lab Tests Online has more information about liver function tests.
About blood testing
Visit healthdirect‘s ‘Guide to blood testing’ to learn more about blood tests in general, including information about:
- what to consider before having a blood test
- what happens during a blood test
- results accuracy
- blood tests cost
Learn more here about the development and quality assurance of healthdirect content.
Last reviewed: August 2018