Liver function tests: what are they looking for?

If your GP would like to refer you for a liver function test, it means that they want to check how well your liver is functioning and whether there is any inflammation or damage inside. These tests are performed to measure the levels of proteins and enzymes in your blood and can determine whether you are at risk of liver disease. We were fortunate to ask one of our expert hepatologists Dr Vikram Sharma all about the tests, including what they are looking for exactly and what the results might mean.

What are liver function tests?

Liver function tests are a panel of blood tests that are frequently requested by GPs and specialists to assess the state of the liver. Along with a full blood count and urea and electrolyte, it is the most routinely requested blood panel to assess the patient’s overall health.

The various component of the liver function indicates the type of liver cells and the disease which might be causing the liver test abnormality.

The liver function test consists of:
 

• Alanine Transaminase (ALT)
• Aspartate Transaminase (AST)
• Alkaline Phosphatase (ALP)
• Gamma Glutaryl Transferase (GGT)
• Total Bilirubin (BIL)
• Total Protein (TP)
• Albumin (ALB)

Specialists will also look at another panel of the blood test to assess the actual function (synthetic function) of the liver. This panel will include:
 

• Total Bilirubin (BIL)
• Albumin (ALB)
• Pro Thrombin Time (PT)
   

What does the 'normal range' mean in liver function tests?

The normal range of blood tests is usually dependent on the laboratory that has conducted the tests. The normal range will most often be given along with the result of the test. If it is not given along with the results, it is important to find out about the normal range from the medical specialists as it might have implication in the assessment and management of the liver function test.

It is important to highlight here that about 5 per cent of patients with advanced liver disease (cirrhosis) will have normal liver function test. Therefore, the results of the blood test will have to be interpreted according to the clinical context in which the request was made.
 

What might it mean if my liver function tests are abnormal?

Most people find out about abnormal liver function when they have a set of blood tests, which include liver function test for an unrelated reason or for routine health checks. It is very important to understand that liver disease is completely asymptomatic in the majority of cases until it is in a very advanced stage.

When a blood test reveals that there is evidence of abnormal liver function, a review from a healthcare specialist is essential. Most of the time, the tests have to be repeated again to confirm the abnormal results and also to assess the trend of liver dysfunction. This will help the health care professional to decide on the seriousness of the condition and refer the patient to the appropriate liver specialist either as an outpatient clinic review or, rarely, directly admitted to hospital for further assessment and treatment.

There are various reasons why liver tests may be abnormal. The most common reasons why liver tests are found to be abnormal in the UK are because of fatty liver, excess alcohol consumption or presence of viral hepatitis like Hepatitis B or C.

Other common causes of abnormal liver tests include medications and herbal supplements. There are many rarer causes of liver test abnormalities, which will be investigated by the liver specialists by doing specific blood tests.
 

What should I do if my liver function tests are abnormal?

When an abnormal blood test is found, the GP will assess the common causes of liver disease. Most commonly, the GP will refer the patient to a liver specialist, also known as a hepatologist, for further advice and guidance on future management.

The hepatologist will take a detailed history, including the amount of alcohol consumption, assess metabolic factors, including diabetes and hypertension, and assess the risk for chronic viral hepatitis including Hepatitis B or C.

The specialist will do an extended set of bloods to assess for rarer causes of liver disease. An ultrasound scan of the liver will also be requested routinely to assess for any focal abnormality of the liver.

Fibroscan is another specialist scan that will be requested by the hepatologist to determine whether there is a presence of any evidence fibrosis or cirrhosis (advanced liver disease). The hepatologist will advise on the management of the liver condition, which could include lifestyle changes or medicines to treat specific liver conditions.
 

How do I keep my liver function healthy?

A balanced diet is fundamental to keep the liver healthy in the long run. There are several examples of a balanced diet which are available online. In general, avoiding high-calorie meals, saturated fat and sugar-containing food is helpful to maintain a healthy liver.

Regular exercise will help with improving metabolism and overall health. The current recommendation is to do 150 minutes of brisk exercise per week.

Avoiding excess alcohol intake will have a big impact in maintaining a healthy liver. The current government guidelines recommend no more than 14 units of alcohol per week.

Other general measures like avoiding toxins like illicit drugs and practising safe sex will prevent transmission of any viral hepatitis.


You can book an appointment with Dr Sharma via his Top Doctor’s profile here if you would like his expert medical opinion in your case.