Liver function (LFTs)
ALT blood test: what a high result means
What an ALT result on a liver function test means, why ALT can be raised, and what to ask your doctor.
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Explain my results → Available on web, iOS & Android.What is ALT?
ALT, or alanine aminotransferase, is an enzyme found mainly in liver cells. When liver cells are irritated or damaged, ALT leaks into the blood, so a raised level is a sign that something is affecting the liver. ALT is part of the liver function tests (LFTs), called a liver panel or hepatic function panel in the US. You may also see it written as SGPT.
Why is this test done?
- As part of routine liver function tests
- To check for liver inflammation or fatty liver
- To monitor medicines that can affect the liver, such as statins or some antibiotics
- To investigate symptoms such as jaundice or abdominal pain
What does a high ALT mean?
A raised ALT means liver cells are being irritated or damaged. Mild rises are common and often linked to lifestyle; the size of the rise and whether it persists matter more than one result.
Possible reasons include:
- Fatty liver disease, often linked to weight, diabetes or alcohol
- Alcohol
- Some medicines and herbal supplements
- Viral hepatitis
- Hard exercise or muscle injury, as ALT is also found in muscle
- Less commonly, autoimmune or inherited liver conditions
What does a low ALT mean?
A low ALT is not usually considered a problem.
Why we don't list a "normal range". Reference ranges differ between laboratories and can depend on your age, sex and whether you are pregnant. The range printed next to your result on your own report is the one that applies to you, so use that, and talk to your doctor about what your result means for you.
What can affect your ALT result?
- Strenuous exercise in the days before the test
- Alcohol
- Medicines and supplements, including paracetamol at high doses, statins and some herbal remedies
- Body weight
Make sense of the whole report, not just one line
Results are easier to understand together. Patiently AI explains your report as a whole and writes personalised questions for your next appointment.
Try it with your own results → Paste, upload or photograph your results.Questions to ask your doctor
- How much is my ALT raised, and is it higher than before?
- What do you think is the most likely cause?
- Do I need further tests, such as a liver scan or hepatitis tests?
- Could my medicines, supplements or alcohol be playing a part?
- What can I do to help my liver?
Frequently asked questions
Is a slightly raised ALT serious?
A mildly raised ALT is common and often caused by fatty liver, alcohol, recent exercise or medicines. Your doctor will usually repeat the test and may look for a cause, especially if it stays raised.
What is the difference between ALT and AST?
Both are liver enzymes. ALT is more specific to the liver, while AST is also found in muscle and the heart. Comparing the two can help suggest the cause of liver irritation.
Can exercise raise ALT?
Yes. Intense exercise, such as heavy weight training, can raise ALT for several days because ALT is also present in muscle.
Can Patiently AI explain my ALT result?
Yes. Paste your results, or upload a photo, PDF or Word file, and Patiently AI explains them in plain English, sticking to the numbers and ranges on your own report rather than adding its own, and suggests questions to ask your doctor. It is free, needs no account, and removes identifying details on your device first.