Blood tests for liver function

Reviewed by our clinical team

The liver is the largest internal organ. The liver works hard to:

• Fight infection
• Remove toxins, such as alcohol
• Balance cholesterol levels
• Support the clotting of blood 
• Release bile – this is a liquid responsible for breaking down fat and aiding digestion 

What is a liver test used for?

A liver blood test (sometimes called a liver function test) is done to understand how well your liver is functioning. Overall, a liver test helps you to see if your liver is diseased, inflamed, infected, or under strain. If the test flags any problems, your doctor is very likely to want to do further tests to work out the reason behind the abnormal result.

What does a liver blood test check?

If you go to your GP, a liver blood test is likely to check:

• Bilirubin – this is a by product of the breakdown of red blood cells. Increased levels can be causes by several things, including alcoholic liver disease and hepatitis.
• Albumin – this is a protein. It transports molecules (including calcium and bilirubin). Too much or too little albumin could mean that you have a problem with your liver or kidneys.
• Total protein – a total protein test will measure the amount of protein in your blood. It can be used to help diagnose liver disease, kidney disease and malnutrition.
• Transferases (alanine aminotransferase and alkaline phosphatase) – these are enzymes. Abnormal levels can indicate problems with the liver. 
• Creatine kinase – this is also an enzyme and is present in all muscle tissue. If raised, it may indicate that the liver is not the source of the problem (it could be muscle related instead). If very raised, it could be because of a heart attack.
• Calcium and corrected calcium – low levels are uncommon and can indicate severe liver disease.
• Prothrombin time or International Normalised Ratio (INR) – this measures the time it takes for the blood to form a clot. It should normally take between 9 – 13 seconds. If the liver is struggling to make enough clotting proteins, clotting time may take longer. 

Can I test my liver function at home?

Yes. LloydsPharmacy Online Doctor offers a general health blood test. It’s a finger prick blood test that is sent via post (it should fit through your letterbox) and then sent back to the laboratory for analysis.

The liver function test is one of several checks and it includes seven biomarkers (the characteristics checked in a blood sample): 

• Total protein
• Albumin
• Globulin
• Alanine aminotransferase
• Alkaline phosphatase
• Gamma-glutamyl transferase
• Bilirubin 

The general health blood test also checks:

• Cholesterol levels - your body needs cholesterol to stay healthy, but too much can increase your risk of heart disease.
• Diabetes risk – this test will help you understand your risk of developing type 2 diabetes or pre-diabetes by looking at your average blood sugar over the past three months.
• Vitamin D levels – it can be hard to get enough vitamin D in the UK we get a lot of it from sun. This test will show you if you have healthy levels.
• Thyroid function – this test checks hormone levels released by thy thyroid. Not enough of these can result in symptoms like weight gain and fatigue.  

Your results will tell you what your biomarker levels are and how they compare to healthy ranges. Our clinicians will contact you with more information if you have any abnormal results. 

How do I keep my liver healthy?

The three main causes of liver disease are:

• Obesity (having a BMI of 30 or higher)
• An undiagnosed hepatitis infection
• Drinking too much alcohol 

Because of this, the risk of developing some types of liver disease can be reduced by healthy lifestyle changes such as:

• Keeping your weight in the healthy range - aim for a BMI between 18.5 and 24.9
• Having the vaccine for hepatitis A and hepatitis B if you’re at risk – learn about the risk factors here
• Cutting down on alcohol – stay under 14 units a week. One unit of alcohol looks like a single shot (25ml) of spirit or half a pint of low to normal strength beer or cider. A small glass of wine served in most pubs (125ml), is equal to 1.5 units.  

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References

https://www.nhsinform.scot/illnesses-and-conditions/stomach-liver-and-gastrointestinal-tract/liver-disease/
https://patient.info/digestive-health/abnormal-liver-function-tests-leaflet
https://www.nhs.uk/conditions/hepatitis/
https://www.southtees.nhs.uk/services/pathology/tests/albumin/
https://www.nhs.uk/conditions/total-protein-test/
https://www.southtees.nhs.uk/services/pathology/tests/creatine-kinase-ck-cpk/
https://patient.info/digestive-health/abnormal-liver-function-tests-leaflet
https://www.gloshospitals.nhs.uk/our-services/services-we-offer/pathology/tests-and-investigations/clotting-screen/
https://www.nhs.uk/conditions/liver-disease/