Do you feel a bit off recently? Maybe you are more fatigued than normal, or your digestion has been acting up. Perhaps you have noticed changes in your skin or eyes, or you simply have a nagging feeling that something is not quite right. These subtle signs could be your body telling you that your liver needs attention.
The liver is one of your body's most vital organs, quietly performing hundreds of essential functions every day. Yet because liver problems often develop silently, many people are unaware their liver is struggling until significant damage has occurred. A liver function test (LFT) can provide crucial insights into your liver health, potentially catching problems early when they are most treatable.
What Is a Liver Function Test?
A liver function test is a blood test that measures various enzymes, proteins, and substances produced or processed by the liver. Despite the name, these tests do not just assess how well your liver is functioning — they can also detect liver damage, inflammation, and certain diseases.
A standard LFT typically includes:
For a comprehensive explanation of what each marker means, read our detailed guide to decoding your liver function tests.
Key Signs You May Need a Liver Function Test
### 1. Unexplained Fatigue
Persistent tiredness that does not improve with rest is one of the most common early signs of liver problems. When the liver is struggling, toxins that would normally be filtered out can accumulate in the bloodstream, causing fatigue and a general feeling of being unwell.
If you are experiencing unexplained tiredness, it is worth investigating. Read our article on why you should not ignore tiredness to learn more about what fatigue could be telling you.
### 2. Digestive Problems
The liver produces bile, which is essential for digesting fats. When liver function is impaired, you may experience:
### 3. Abdominal Discomfort
Pain or discomfort in the upper right area of your abdomen, where the liver is located, can indicate liver inflammation or enlargement. This may feel like a dull ache or a sense of fullness.
### 4. Skin and Eye Changes
The liver processes bilirubin, a yellow pigment. When the liver cannot process bilirubin properly, it accumulates, causing:
For more information about bilirubin and what elevated levels mean, read our guide to understanding bilirubin tests.
### 5. Dark Urine
When bilirubin levels rise, excess bilirubin is excreted through the kidneys, causing urine to become dark brown or tea-coloured. This is often one of the first noticeable signs of liver problems.
### 6. Swelling
Advanced liver disease can cause:
These occur when the liver cannot produce enough albumin, leading to fluid leaking out of blood vessels.
### 7. Unexplained Weight Changes
Both weight loss (due to loss of appetite and muscle wasting) and weight gain (due to fluid retention) can occur with liver problems.
Risk Factors That Warrant Testing
Even without symptoms, you should consider a liver function test if you have risk factors for liver disease:
Lifestyle factors:
Medical factors:
Occupational factors:
Common Liver Conditions LFTs Can Detect
### Non-Alcoholic Fatty Liver Disease (NAFLD)
NAFLD is the most common liver condition in the UK, affecting up to 30% of the population. Fat accumulates in the liver, potentially causing inflammation and damage. It is strongly associated with obesity, diabetes, and metabolic syndrome.
### Alcoholic Liver Disease
Excessive alcohol consumption damages the liver progressively, from fatty liver to alcoholic hepatitis to cirrhosis. LFTs, particularly GGT, are sensitive indicators of alcohol-related liver damage.
### Viral Hepatitis
Hepatitis B and C can cause chronic liver inflammation and, if untreated, cirrhosis and liver cancer. LFTs help monitor liver damage, though specific viral tests are needed for diagnosis.
### Drug-Induced Liver Injury
Many medications can affect the liver. Regular LFTs are important if you take medications known to have hepatotoxic potential.
For comprehensive information about liver health and what blood tests reveal, read our article on liver health matters.
What Happens During the Test?
A liver function test is a simple blood test:
For general information about the blood testing procedure, read our comprehensive overview of blood testing.
Interpreting Your Results
LFT results should always be interpreted by a healthcare professional, as:
When to Act
Do not wait for obvious symptoms to appear. The liver has remarkable regenerative capacity, meaning it can be significantly damaged before symptoms develop. Early detection through blood testing allows for intervention when treatment is most effective.
If you have risk factors or any concerning symptoms, a liver function test provides valuable peace of mind or early warning.
Liver Function Testing in London
At Private Blood Tests London, we offer comprehensive liver function panels at our CQC-registered clinic in South Kensington. Our tests provide detailed insights into your liver health, with results typically available within 24-48 hours.
For a complete understanding of your liver markers, read our detailed guide to [decoding your liver function tests](/blog/decoding-your-liver-function-tests-lfts) and explore our [liver function test page](/liver-function-test).
Your liver works hard for you every day. Find out how it is doing. Book your liver function test today.