--- title: "Liver function tests (LFTs): What to Expect | HealthAnswers" description: "Liver function tests measure enzymes and proteins in the blood to detect liver inflammation, fatty liver disease and other liver conditions." url: https://healthanswers.co.uk/tests/liver-function-test/ robots: noindex --- # Liver function tests (LFTs): What to Expect | HealthAnswers Tests & investigations Liver function tests measure enzymes and proteins in the blood to detect liver inflammation, fatty liver disease and other liver conditions. Written by HealthAnswers editorial team Medically reviewed by [HealthAnswers UK doctor review panel](https://healthanswers.co.uk/our-doctors/) Reviewed 3 July 2026 ## 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. ## Who is this page for? This page is for people in the UK who want a plain-English overview of Liver function tests (LFTs), including when to seek help and what NHS care usually involves. It explains general information, not what is wrong with you personally. ## Who should skip this page? Skip this page if you need a diagnosis, a prescription, or emergency care. It cannot replace a GP, pharmacist, NHS 111 or 999. If you are in immediate danger, call 999; for urgent advice that is not life-threatening, call 111 in England, Scotland or Wales, or use your GP out-of-hours service in Northern Ireland. On this page 4 sections ## Key facts about the liver function tests - ALT and AST levels indicate damage to liver cells. - Alkaline phosphatase and bilirubin are also measured in the test. - Fatty liver is a common cause of a mild rise in results. - Alcohol and certain medicines can affect LFT results. - Hepatitis viruses are tested for separately from LFTs. ## 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. ## ! When to speak to a doctor about the liver function tests See a GP if you have abnormal LFTs, and do not ignore unexplained results. Call **111** for urgent advice when you are unsure what to do. ## 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. ## Sources - [NHS — Liver Blood Tests](https://www.nhs.uk/conditions/liver-blood-tests) - [NHS — Non Alcoholic Fatty Liver Disease](https://www.nhs.uk/conditions/non-alcoholic-fatty-liver-disease)