Blood test
Liver Function Test (LFTs)
Liver function tests are a group of blood tests that check how well your liver is working by measuring enzymes and proteins it makes. They help find and monitor liver problems.
Quick answer
Liver Function Test (LFTs): what it is and what the results mean
Liver function tests (LFTs) are a panel of blood measurements — including enzymes such as ALT, AST, ALP and GGT, along with bilirubin and the protein albumin — that together reflect the health of the liver and bile system.
- Why it is done: They are used to investigate symptoms such as jaundice, tiredness or abdominal pain, to check for liver damage from alcohol, medicines, fatty liver or hepatitis, and to monitor known liver conditions over time.
- Understanding results: Raised enzymes can suggest liver inflammation or injury, while a high bilirubin may explain jaundice and a low albumin can reflect longstanding liver disease.
What it is
Liver function tests (LFTs) are a panel of blood measurements — including enzymes such as ALT, AST, ALP and GGT, along with bilirubin and the protein albumin — that together reflect the health of the liver and bile system.
Why it is done
They are used to investigate symptoms such as jaundice, tiredness or abdominal pain, to check for liver damage from alcohol, medicines, fatty liver or hepatitis, and to monitor known liver conditions over time.
What to expect
A standard blood sample is taken from a vein in the arm. Fasting is not usually needed. Results are typically available within a day or two.
Understanding the results
Raised enzymes can suggest liver inflammation or injury, while a high bilirubin may explain jaundice and a low albumin can reflect longstanding liver disease. A single mildly abnormal result is common and often harmless; the pattern is interpreted alongside your symptoms and other tests.
Good to know
Risks and limitations
Risks are those of a routine blood test — brief discomfort or minor bruising. LFTs show that something may be affecting the liver but do not, on their own, give the exact cause, so further tests such as scans are sometimes needed.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
Liver Function Test (LFTs): frequently asked questions
What do liver function tests check for?
They measure enzymes and proteins made by the liver to look for inflammation, damage or problems with bile flow — from causes such as alcohol, fatty liver, hepatitis or certain medicines.
Do I need to fast before a liver function test?
Usually no. Fasting is not normally required for standard LFTs, though your clinician will tell you if it is being combined with other tests that do need it.
Related tests
Other blood test investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- Royal College of Pathologists / relevant professional body
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