Liver blood tests

Liver blood tests are very common. They are often asked for by a GP:

to check on the liver
to help diagnose or rule out a liver condition
as part of regular checks for a medical condition or on the medicines someone is taking

It is very common to have some liver blood test results that are not normal. This does not always mean that someone has a long term or serious liver problem.

On this page you can find out more about having a liver blood test, what the results might mean, and what should happen next.

This test used to be called a liver function test or LFT.

On this page:

Home testing for liver disease

We do not recommend any home liver tests apart from the free NHS hepatitis C test.

Home tests on their own cannot tell if someone has a liver condition or not. If you have any concerns about your liver, or about someone you care for, speak to your GP. Adults can also find out about their risk factors using our free and confidential at-risk checker.

Find out more about home liver blood tests here.

Having a liver blood test

A liver blood test is actually several different tests. But usually only one blood sample is needed.

Sometimes it is a “fasting blood test”. This means the person having the test will be asked not to eat anything overnight or in the morning before the test. They will only be able to drink water. Not all liver blood tests have to be done after fasting.

Tell the doctor about any prescription medicines, over the counter medicines, herbal and natural remedies, and supplements. These can sometimes affect the results.

You can ask the person taking the blood sample how long it will take to get the results. This should usually be within 2 weeks.

What will be tested?

Different labs have different versions of the liver blood test. In most cases the test will look at the levels of:

bilirubin
proteins, such as albumin, made in the liver
some of the enzymes made in the liver

Enzymes are a type of protein. They help the liver

AST (enzyme)

Stands for: aspartate aminotransferase

Also called : serum glutamic-oxaloacetic transaminase, SGOT

AST is an enzyme that is made in the liver. It is also made in the heart, muscles and some of the other tissues in the body. AST leaks out into the blood stream when one of these body parts is injured. This causes an increase in the AST level in the blood.

ALT (enzyme)

Stands for: alanine aminotransferase

ALT is an enzyme that is mostly found in the liver. If the liver is damaged the ALT level in the blood can go up.

ALP (enzyme)

Stands for: alkaline phosphatase

ALP is an enzyme that is mostly found in the liver and bones. A high level of ALP in the blood can mean that there is a problem with the liver or bile ducts. The ALP level can sometimes be higher in other conditions that do not involve the liver.

GGT (enzyme)

Stands for: gamma-glutamyl transferase

GGT is an enzyme found mostly in the liver. If the liver or bile ducts are damaged, then GGT can leak out and the GGT level in the blood will go up.

Bilirubin

Bilirubin is made when old or damaged red blood cells are broken down. Usually the liver removes bilirubin from the blood. But if the liver is damaged there can be a higher level of bilirubin in the blood.

Having too much bilirubin in the blood can also cause jaundice. This is a yellow colour to the eyes or skin. How severe the jaundice is can be linked to how high the level of bilirubin is. But other things can also affect this.

Doctors sometimes compare the amount of conjugated and unconjugated bilirubin. This can help them to work out if the overall bilirubin level is being caused by a problem with bile flow or a problem with how red blood cells are broken down. Conjugated bilirubin has a sugar added to it. Unconjugated bilirubin does not have this sugar.

Albumin (protein)

Albumin is a very important protein. It has several jobs, including making sure that fluid cannot leak out of the blood vessels. It is made in the liver. If the liver is damaged it can struggle to make enough albumin so the level of albumin in the blood will go down.

Total protein

A total protein test looks at all the protein in part of the blood called plasma. The most common proteins are albumin and antibodies (also called immunoglobulins). If the liver is damaged it might make less albumin so there will be less total protein in the blood.

You will probably not be tested for all these things. You might be tested for some extra things as well.

Questions to ask the doctor

Why have you asked for a liver blood test?
Can I, or my child, eat before I having the test?
How and when will I get the results?
Who can I talk to if I have questions about the results?

Understanding liver blood test results

The results will be compared to a reference range. Sometimes called a “normal range”.

The same test can have lots of different reference ranges. It is important to only compare your, or your child’s, results with the range set by the lab that did the test. Different labs have different reference ranges. There can also be different ranges for men and women, and by age.

You can find out more about reference ranges here.

The results of each individual test only give part of the picture. The doctor will look at all the results together to decide if there could be a problem that needs more tests.

Some results can be caused by problems that are not in the liver. Results can also be affected by things like:

Age
Ethnicity
If someone is male or female
If someone is overweight
Diet
Some medicines
Other medical conditions

The doctor will look at all these things along with the test result. You will usually just be told if the overall result is “normal” or not.

What does it mean if the results are “normal”?

A normal liver blood test is a good sign that the liver is probably doing okay.

But it is worth remembering that the liver can take a lot of damage before it starts to have any problems. Taking action now could help keep the liver healthy in future.

Ways to keep the liver healthy:

Avoiding alcohol or keeping to the recommended limits.

Eating a healthy balanced diet.

Staying active.

Not smoking.

Getting tested for viral hepatitis if this could be a risk.

It is possible for someone to get a normal liver blood test when they have a serious liver condition. If someone is at high risk of liver disease, or has any symptoms, they should be referred or have more tests.

Adults can find out if you might be at risk of liver disease by taking our free at-risk chcker. The results are completely confidential and will not be shared with anyone. At-risk checker

You can find out more about the symptoms of liver disease here.

Questions to ask the doctor:

How certain are you that there is not a liver problem?
If the liver is not causing the problem, what should be done next to deal with the symptoms?
What can I do to help keep the liver healthy?
Are there any local support services that could help?

What does it mean if the results are not “normal”?

It is quite common to get a result that is not normal. This does not always mean that someone has a liver condition. But it could mean that more tests are needed to find out what is going on.

The results can help to narrow down what might be wrong with the liver so that doctors know which tests to do next.

In almost 1 in 3 cases, results go back to normal by themselves in about 3 weeks. So the doctor might ask for another test in a few weeks to see if this happens.

Questions to ask the doctor:

Should the blood test be repeated to see if things go back to normal?
Which of the results are not normal?
What are all the possible things that could be causing that result?

What if the results are just outside the reference range?

You might be told that some of the results are just outside the reference range. Or close to the edge of it. This is often nothing to worry about.

1 in 20 test results from healthy people are outside the reference range. The full range of possible results is often many times bigger than the reference range.

It could be that there is something else affecting the result. Or that the results go up and down a bit over time.

Questions to ask the doctor:

Why do you think the results are not in the reference range?
Should the liver blood test be repeated to see if it changes?
Are any other tests needed?

What should happen next

If the results suggest that there could be a problem the GP might use them to calculate something called the FIB-4 index. The Fib-4 index gives an indication of the amount of scarring (fibrosis) in the liver.

Depending on results, age, and if you know what might be causing the liver condition, the GP might ask for:

more one-off tests
regular tests to check on the liver

Or they may make a referral to a gastroenterology department. This is a hospital department that deals with problems with the digestive system. Or to a hepatology department, this is a specialism that only deals with the liver.

You may be able to choose where you or your child are referred to. You can find out more about this here.

After being referred, the next step will depend on the type of liver condition that might be causing the problem.

More blood tests are often needed, sometimes called a full liver screen or non-invasive liver screen.

Doctors might also ask for an imaging test such as an ultrasound or FibroScan.

You can find out more about other tests for liver disease here.

Questions to ask the doctor

Should I, or my child, be referred to a specialist and why or why not?
Where will this referral be? Do I have any choices?
What are the waiting times like?
Do you have any recommendations about where to be referred to, based on what other patients have told you?
Who should I contact if the condition gets worse before the next appointment?
Are there any “red flag” symptoms I should look out for? What should I do if they happen?
Is there anything I can do while waiting for the referral?

Useful links
Tests for liver disease
Liver conditions
Living with a liver condition
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This content was last reviewed: July 2025

Our expert reviewers:

We would like to thank everyone who helped with creating and reviewing this page. Including Professor Stephen Ryder, consultant hepatologist at Nottingham University Hospitals NHS trust and Dr Laura-Jane Armstrong, Associate GP, Avonside Health Centre. And all our patient reviewers.

Find out how we make our patient information.

Everyone’s experience of liver disease will be different. Always talk to your specialist medical team for personal advice.