A liver function test is a blood test that measures the enzymes and proteins your liver makes, so you can see how well the organ is working and pick up early signs of stress before symptoms appear. It typically looks at markers like ALT, AST, GGT, ALP, bilirubin and albumin. Raised levels can flag inflammation or damage from causes such as alcohol, fatty liver, certain medications or viral hepatitis. Because the liver often shows no obvious symptoms in the early stages, a simple test is one of the clearest ways to check in on it. With Alcohol Awareness Week running from 6 to 12 July 2026, it is a useful moment to understand what the test reveals.
In this article
- What does a liver function test actually check?
- What are the warning signs of liver problems?
- How does alcohol affect your liver?
- Should you get a liver function test?
- Can you do a liver function test at home?
- Frequently asked questions
What does a liver function test actually check?
Despite the name, a standard liver function test is really a panel of separate markers. Most are enzymes that leak into the blood when liver cells are irritated or damaged, plus a couple of proteins that show how well the liver is doing its everyday jobs. Reading them together gives a clearer picture than any single result on its own.
| Marker | What it is | Why it matters |
|---|---|---|
| ALT | Alanine aminotransferase, an enzyme mostly found in the liver. | The most liver-specific marker. A raised level can point to liver cell damage. |
| AST | Aspartate aminotransferase, found in the liver but also heart and muscle. | Read alongside ALT. The ratio between them can hint at the cause. |
| GGT | Gamma-glutamyl transferase, an enzyme in the liver and bile ducts. | Often raised with regular or heavy alcohol intake and bile duct issues. |
| ALP | Alkaline phosphatase, linked to the bile ducts and bone. | High levels can suggest a blockage or problem with bile flow. |
| Bilirubin | A waste product the liver clears from the blood. | When it builds up it can cause jaundice, a yellowing of skin or eyes. |
| Albumin | A protein the liver makes. | A low level can reflect how well the liver is performing over time. |
A single mildly raised result is common and not always a cause for concern. The pattern across markers, your history and a clinician's interpretation are what matter. The British Liver Trust has a helpful plain-English guide to what each result can mean.
What are the warning signs of liver problems?
The tricky part is that early liver disease frequently has no symptoms at all, which is why testing is so useful. When signs do appear, they can include:
- Ongoing tiredness or low energy
- Yellowing of the skin or the whites of the eyes (jaundice)
- Pain or discomfort in the upper right side of the tummy
- Feeling sick, a poor appetite or unexplained weight loss
- Itchy skin, or bruising more easily than usual
- Swelling in the legs, ankles or abdomen
These symptoms can have many causes and do not confirm a liver problem on their own. If you notice them, a liver blood test is a sensible first step, and you should speak to your GP about anything persistent.
Checks the key liver enzymes and proteins, including ALT, AST, GGT and bilirubin, to investigate liver function and look for signs of liver stress.
How does alcohol affect your liver?
Your liver processes most of the alcohol you drink. Over time, regular drinking above the guidelines can lead to fat building up in the liver, then inflammation, and in some cases lasting scarring. The early stages, including fatty liver, can often improve if drinking is reduced, which is part of why catching changes early matters.
This is the backdrop to Alcohol Awareness Week (6 to 12 July 2026). According to the British Liver Trust, around 9 in 10 cases of liver disease are preventable, and deaths from alcohol-related liver disease in the UK have risen sharply over the past decade. The UK Chief Medical Officers advise keeping to no more than 14 units a week, spread over three or more days. You can check your own intake with the NHS alcohol units calculator.
Alcohol is not the only factor. Diet, weight and physical activity all play a part, and a few alcohol-free days each week give your liver time to recover. For ideas on eating well for your liver, see our guide to the top 10 foods for a healthy liver.
Should you get a liver function test?
A liver function test can be worth considering if you want a clearer picture of your health. It is often chosen by people who:
- Drink regularly and want to understand the effect on their liver
- Are carrying extra weight or have been told they may have fatty liver
- Take long-term medication that can affect the liver
- Have a family history of liver conditions
- Simply want a baseline as part of a general health check
If you would rather see your liver markers alongside cholesterol, kidney function and blood sugar, a broader panel can give more context in one sample.
A broad check that includes liver markers along with cholesterol, kidney function and more, for a fuller view of your general health.
Can you do a liver function test at home?
Yes. A liver test at home uses a small finger-prick blood sample that you post to an accredited laboratory, with results sent to you online. If you prefer, a clinician can take the sample at one of Goodbody's clinics, or a nurse can visit you at home. Here is how the options compare.
| Option | How the sample is taken | Good for |
|---|---|---|
| Home finger-prick | You collect a small sample yourself with the kit provided. | Convenience and testing on your own schedule. |
| In-clinic | A professional takes a venous blood sample at a clinic. | Those who prefer a trained clinician to draw the sample. |
| Home nurse visit | A nurse comes to your home to take the sample. | Comfort of home with a professional draw. |
If you want the most thorough overview, our most comprehensive panel checks dozens of biomarkers in a single appointment, including liver, heart and hormone health.
Analyses 61 key health biomarkers in one sample, including a full liver panel, for a complete picture of your health.
Frequently asked questions
Do I need to fast before a liver function test?
A standalone liver test usually does not require fasting. If your liver markers are part of a wider panel that includes cholesterol or glucose, you may be asked to fast beforehand. Always follow the instructions that come with your test.
How long do liver function test results take?
With Goodbody, results are typically available online within a few days of the laboratory receiving your sample. Exact timing depends on the test and how the sample is taken.
Can a liver function test detect fatty liver?
It can flag changes that may be linked to fatty liver, such as a raised ALT, but it cannot diagnose it on its own. Abnormal results are usually followed up with further assessment by a clinician, which may include a scan.
What is a normal liver function test result?
Each marker has its own reference range, and laboratories can differ slightly. Results are best read together and in the context of your health rather than judged one number at a time. Your report will show the ranges used.
How often should I check my liver?
There is no single rule. Many people use a liver or general health test once a year as a baseline, or sooner if they want to track a change, such as cutting back on alcohol. Your GP can advise on what is right for you.
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This article is general information and is not medical advice. It is not a diagnosis and does not replace a consultation with a qualified healthcare professional. If you have symptoms or concerns about your liver or your drinking, please speak to your GP. Pricing is correct at the time of writing and may change, see goodbodyclinic.com for current prices.