Quick answer
What are liver function tests?
Liver function tests (LFTs) are blood tests that measure enzymes and proteins produced by the liver, helping to detect inflammation, fatty liver, alcohol-related liver disease and hepatitis. Fasting is often not required. Abnormal results need review by your GP and sometimes an ultrasound scan.
Purpose of liver function tests
Liver function tests are used to assess inflammation in the liver and how well it is functioning overall. They are also used to monitor people with a known liver condition and to check the effects of certain medicines on the liver.
Interpreting liver function test results
Mild rises in liver function tests are common, and your GP will often repeat the test to see how the results trend over time. The particular pattern of results can suggest whether the problem relates to the liver cells themselves or to the bile ducts.
Common causes of abnormal liver function tests
Non-alcoholic fatty liver disease, alcohol, certain medicines and viral hepatitis are among the most common causes of abnormal results. Gallstones can also affect the bile-related markers measured in the test.
Follow-up after abnormal liver function tests
Follow-up often involves lifestyle advice such as reducing alcohol intake and losing weight where relevant. A referral to a specialist may be needed if the abnormality persists or is significant.
Common questions about the liver function tests
- What causes raised liver function tests?
- Raised liver function tests can be caused by fatty liver, alcohol, certain medicines, viral hepatitis or gallstones. There are many possible causes, so further tests are often needed to pinpoint the reason.
- What does fatty liver look like on liver function tests?
- Fatty liver is a very common cause of mildly raised liver function tests and is linked to weight, diabetes and alcohol intake. Lifestyle changes such as weight loss often help improve the results.
- Do I need to stop drinking alcohol before a liver function test?
- No, you do not need to fast or stop drinking before a liver function test. However, you should tell your GP about your usual alcohol intake so they can interpret the results properly.
- What further tests might follow abnormal liver function tests?
- Further tests may include an ultrasound scan, hepatitis serology or a FibroScan, depending on the pattern of your results. Your GP will decide which tests are appropriate for your situation.