Liver panel

What is it?
A liver panel, also known as liver function tests or LFTs, is used to detect, assess and monitor liver disease or damage. It normally consists of seven tests carried out at the same time on a blood sample. These are:

• Alanine aminotransferase (ALT): an enzyme found mainly in the liver; the best test for detecting hepatitis
• Alkaline phosphatase (ALP): an enzyme linked to the bile ducts; it often rises when they are blocked
• Aspartate aminotransferase (AST): an enzyme found in the liver and in smaller amounts elsewhere, particularly the heart and other muscles
• Bilirubin: two different bilirubin tests are often used together (especially if a person has jaundice): total bilirubin measures all the bilirubin in the blood; direct bilirubin measures a form that is conjugated (combined with another compound) in the liver
• Albumin: measures the main protein made by the liver and shows whether the liver is making enough of it
• Total protein: measures albumin and all the other proteins in the blood, including the antibodies made to help fight infections.

Other tests that may be requested together with the liver panel are gamma-glutamyl transferase (GGT), lactate dehydrogenase (LDH) and prothrombin time (PT).

When are they requested?
One or more of these tests may be requested when there are symptoms suggesting liver disease. These are: jaundice, dark urine or pale bowel movements; nausea, vomiting and/or diarrhoea; loss of appetite; vomiting blood; bloody or black bowel movements; swelling or pain in the abdomen; unusual weight change; or tiredness or loss of strength. One or more of these tests may also be requested when a person has been or may have been exposed to hepatitis viruses, has a family history of liver disease, drinks too much alcohol, or is taking a medicine that can cause liver damage.

Many patients with early or mild to moderate liver disease may have few of these symptoms. Liver disease may first be detected through routine tests requested as part of a medical check-up. These include a group of 14 tests called the comprehensive metabolic panel (CMP). Most of the tests in the liver panel (all except direct bilirubin) are included in the CMP. When liver disease is detected with a CMP, it can be monitored over time with follow-up liver panels.