A liver function test (LFT) is a blood test that measures the levels of several substances (enzymes and proteins) produced by your liver. This can give an indication of the condition of your liver.
This page is a short summary about liver function tests. For more detailed information, see Liver function tests (LFT) – in-depth.
What is a liver function test?
A liver function test (also called LFT) is a blood test that can provide information about how well your liver is working or if it is under stress. The test measures the levels of a number of proteins and enzymes produced by liver cells. The substances are released when liver cells are damaged or when the flow of bile through the liver is blocked. The pattern of abnormalities can give a clue as to the cause of the liver problem.
When are liver function tests measured?
Liver function tests are usually performed to:
- test for liver disease and give an indication of how severe the disease is
- monitor somebody who is known to have liver disease
- find out how well a treatment is working
- monitor side effects if you are taking prescription or non-prescription medicines that can affect your liver function.
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Read more about liver disease.
What does it mean if the result is abnormal?
Interpreting liver function test results is complicated and is best done in consultation with your healthcare team. They will know what is normal for you and how these results relate to your other signs and symptoms.
They are not perfect tests. Abnormal values can be found if you have other health conditions, not related to the liver. For some people with very severe liver disease the levels may be normal.
The most common causes for elevated liver function tests are alcohol consumption and fatty liver due to obesity.
Learn more
The following is further reading that gives you more information on having a blood test and the liver function tests. Be aware that websites from other countries may contain information that differs from NZ recommendations.
Blood test safety information Labtests, NZ
Liver function tests Patient Info, UK
Liver function tests Australasian Association of Clinical Biochemists