17662 Liver Function Tests

Overview

Liver function tests — often called LFTs — are a group of blood tests that give a picture of how well your liver is working. Your liver is a large organ in the upper right side of your belly. It cleans your blood, helps digest food, stores energy, and fights infection. The tests measure levels of certain enzymes (proteins that speed up body reactions) and other proteins in your blood. Some of these come from liver cells, and some are made by the liver. When liver cells are irritated, inflamed (swollen), or damaged, these levels can change. It is important to know that an abnormal result does not mean you have liver disease. It is a clue that your doctor will look into further.

Very common. Liver function tests are one of the most frequently ordered blood tests in general practice. They are often part of a routine check-up, a health screening, or tests done before starting a new medicine. Because they are ordered so often, mildly unusual results are something doctors see every day.

Anyone can have liver function tests. They are done at all ages, from newborns being checked for jaundice (yellowing of the skin and eyes) to older adults having routine health checks. You may be offered them if you have symptoms that could point to a liver problem, if you take medicines that can affect the liver, or if you have a condition such as diabetes, high blood pressure, or a high body weight.

Symptoms

Common symptoms

• The test itself has no symptoms — it is just a blood draw.
• Many people with slightly abnormal results feel completely well and are surprised by the result.
• Feeling more tired than usual, or lacking energy.
• A dull ache or discomfort in the upper right part of the belly.
• Feeling sick or off your food.
• Yellowing of the whites of the eyes or the skin (this is called jaundice).
• Dark urine, or pale, chalky stools.
• Itchy skin.
• Swelling in the belly or ankles.
• Bruising or bleeding more easily than usual.

Symptoms in children

• Jaundice is common in newborns and is usually harmless and brief, but jaundice lasting beyond about two weeks should be checked.
• Poor feeding, being unusually sleepy, or not gaining weight in a baby.
• In older children: tiredness, tummy pain, feeling sick, or yellowing of the eyes.
• Some children have mildly raised liver results with no symptoms at all, found on a routine blood test.

Symptoms in older adults

• Symptoms may be vaguer than in younger people — for example, low energy, poor appetite, or general weakness.
• Confusion or unusual drowsiness can sometimes be a sign of a liver problem in older adults and should be checked quickly.
• Yellowing of the eyes may be noticed before any other change.
• Bruising after minor knocks may be more noticeable.
• Some medicines taken for other conditions can affect liver test results, so bring a full list of your medicines to your appointment.

Causes

Main causes

• Fatty liver — extra fat stored in liver cells, often linked to body weight, diabetes, or alcohol.
• Alcohol, especially regular heavy drinking.
• Viral infections of the liver, such as hepatitis B and hepatitis C.
• Side effects of some prescription medicines, over-the-counter pain relievers, and herbal or body-building supplements.
• Gallstones or a blocked bile duct (the tube that carries digestive fluid from the liver).
• The body's immune system attacking the liver (autoimmune liver conditions).
• Inherited conditions, such as haemochromatosis (too much iron stored in the body) or Wilson's disease.
• A recent infection or illness elsewhere in the body.
• Intense or unaccustomed exercise, which can briefly raise some enzyme levels.
• In pregnancy, some changes in liver tests are normal, but others need checking.
• In children, prolonged jaundice in a newborn or certain inherited conditions.

Risk factors

• Carrying extra weight around the belly, or having type 2 diabetes.
• Drinking alcohol regularly or heavily.
• Having a family member with liver disease.
• Conditions spread through blood or unprotected sex that affect the liver, such as hepatitis B or C.
• Having had a blood transfusion or medical procedure in a country where hepatitis is common.
• Taking several medicines at once, or taking herbal and body-building supplements.
• Getting little physical activity.
• High cholesterol or high blood pressure.

When to see a doctor

See a doctor urgently if:

• You notice yellowing of your eyes or skin.
• You have dark urine and pale stools.
• Your belly or legs are swelling.
• You are bruising or bleeding easily.
• You have a fever with tummy pain.
• You feel very drowsy or confused.

Book a routine appointment if:

• You have been told you have an abnormal liver function test result and have not yet discussed it.
• You feel unusually tired for more than a few weeks.
• You have an ongoing ache in the upper right part of your belly.
• You are planning to start a new medicine or supplement and want to know if it could affect your liver.
• You have risk factors for liver disease, such as regular heavy drinking or a family history.
• You have itchy skin that will not settle.

Diagnosis

Liver function tests are diagnosed — or rather, done — by taking a sample of blood, usually from a vein in your arm. You do not need to do anything special beforehand, though your clinic may ask whether you have eaten. The laboratory measures several things. Common ones include ALT and AST (enzymes found inside liver cells), ALP and GGT (enzymes linked to the bile ducts), bilirubin (a yellow substance the liver processes), and albumin (a protein the liver makes). Your doctor compares your numbers with the normal range for your age and sex, then looks at the pattern. If a result is only slightly outside the range, the usual next step is simply to repeat the test after a few weeks.

Tests that may be done

• A blood sample for liver function tests (the main test).
• A repeat blood test after a few weeks, to see whether the result settles.
• Blood tests for hepatitis B and hepatitis C.
• Blood tests for other conditions, such as thyroid problems, coeliac disease, or iron levels.
• An ultrasound scan of the upper belly to look at the liver, gallbladder, and bile ducts.
• A special scan that measures how stiff the liver is (sometimes called a FibroScan) — this checks for scarring without any needle.
• Occasionally, a small sample of liver tissue taken with a thin needle (a liver biopsy) if other tests do not explain the results.

What to expect at your appointment

The blood test takes a few minutes. You may feel a small pinch when the needle goes in, and a mild bruise afterwards is normal. Results usually come back within a few days, though this varies by service. If your result is only mildly raised, you may be asked to come back for a repeat test rather than having lots of other tests straight away. If further tests are needed, your doctor will explain why and what each one involves. You are welcome to ask for a printed copy of your results and to have the numbers explained to you.

Treatment

Liver function tests are not a condition, so there is no treatment for the test itself. What happens next depends on what the results show and what is causing any change. Often the answer is simply to repeat the test, make some healthy changes, and check again. If a cause is found, the treatment targets that cause. Your doctor will explain the plan in plain terms and involve you in decisions.

Self-care at home

• Cut down on or stop drinking alcohol while your results are being checked — your doctor can advise what is safe for you.
• If you take herbal supplements, protein powders, or body-building products, tell your doctor or pharmacist. Some can affect the liver.
• Bring a full list of all your medicines, including anything you buy without a prescription, to each appointment.
• Aim for a healthy weight if you are carrying extra weight — even a modest loss can improve liver results.
• Stay active with regular movement you enjoy, such as walking, swimming, or cycling.
• Eat a balanced diet with plenty of vegetables, fruit, and whole grains, and go easy on sugary drinks.
• Get enough sleep and rest, especially if you are feeling tired.
• Never start a new supplement or 'liver detox' product without checking with your pharmacist or doctor first.

Medical treatments

Treatment is aimed at the underlying cause. For fatty liver, the main approach is healthy eating, physical activity, and gradual weight loss — this can genuinely reverse the changes. If alcohol is a factor, your doctor can offer support and referral to alcohol services. If a medicine is thought to be the cause, your doctor may adjust or change it — never stop a prescribed medicine yourself without advice. Viral hepatitis can now be treated effectively with courses of medicine prescribed by a specialist. Autoimmune liver conditions are managed by dampening the immune system's attack, under specialist care. If the bile ducts are blocked, a procedure to clear them may be arranged. Your doctor will discuss which of these, if any, applies to you.

When is surgery considered?

Surgery or a procedure is only needed in specific situations. Examples include removing gallstones that are blocking the bile ducts, or placing a small tube (a stent) to keep a narrowed duct open. In rare cases of advanced liver disease, a liver transplant may be considered and would be discussed with a specialist team. Most people having liver function tests never need any of these.

Living with this condition

Most people with a mildly abnormal liver test carry on with normal life while the cause is being checked. Keep a note of your results and appointments, and ask questions if anything is unclear. If you have been given a diagnosis, you may need occasional check-ups or blood tests — these are to keep you well, not a sign that something is going wrong.

Lifestyle tips

• Keep alcohol within the limits your doctor advises, or avoid it if you have been told to.
• Build activity into your day — a brisk walk most days makes a real difference.
• Choose water or unsweetened drinks instead of sugary ones.
• Aim for gradual, steady weight loss rather than crash diets.
• Wash your hands well and avoid sharing razors, toothbrushes, or needles, to protect your liver from infections.
• Get vaccinated against hepatitis if your doctor recommends it.
• Tell any healthcare professional you see that you have had liver test changes.

Diet and exercise

A Mediterranean-style way of eating is often recommended for liver health — plenty of vegetables, fruit, beans, whole grains, olive oil, fish, and nuts, with less processed food, fried food, and sugar. You do not need a special 'liver diet' or expensive supplements. For activity, aim for something you will actually keep doing: walking, gardening, dancing, or swimming all count. If you are new to exercise, start gently and build up. If you have other health conditions, ask your doctor what is safe for you.

Mental health and emotional wellbeing

Being told a test result is abnormal can cause worry, poor sleep, and a lot of internet searching. That reaction is very normal. Try to get your information from your own doctor or a trusted health service rather than random websites, and write down your questions before appointments. If anxiety is affecting your daily life, tell your doctor — support such as talking therapies is available. If you ever feel you cannot cope, please contact your doctor or a local crisis support service straight away; in an emergency, call your local emergency number.

Prevention

Many liver problems that show up on these tests can be prevented or improved. Keeping to a healthy weight, limiting alcohol, eating well, and staying active all protect the liver. Checking with a pharmacist before taking new supplements or combining medicines helps avoid accidental harm. Good hand hygiene and safer practices around needles and sex reduce the risk of viral hepatitis.

Vaccines

Vaccines are available in many countries to protect against hepatitis A and hepatitis B. Ask your doctor or pharmacist whether these are recommended for you — for example, if you travel to certain regions, work in healthcare, or have a long-term liver condition.

Screening programmes

Many health services offer routine blood tests, including liver function tests, as part of a general health check, especially if you have risk factors such as diabetes or a high body weight. Screening for hepatitis B and C is offered in some countries to people at higher risk, and to pregnant women. If you think you may be at risk, ask your doctor whether testing is right for you.

Complications

If left untreated

• Ongoing inflammation can, over many years, lead to scarring of the liver (fibrosis, and later cirrhosis).
• A badly scarred liver may not work properly, causing tiredness, fluid build-up, and bleeding problems.
• Some long-term liver conditions increase the risk of liver cancer, so people with cirrhosis are usually offered regular checks.
• A blocked bile duct that is not treated can cause infection and serious illness.
• Some liver problems can affect how the body handles medicines, so doses may need review.

Long-term outlook

The outlook is good for most people. Mildly abnormal results often return to normal on their own, and fatty liver can improve a great deal with healthy eating, activity, and less alcohol. Viral hepatitis can now be cured in most people with treatment. Finding a problem early is a real advantage, because there is more that can be done. Whatever your result, your doctor will work with you on a clear plan.

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