This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

LFTs

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

Liver function is assessed by a battery of tests which generally include a minimum of plasma bilirubin, albumin, and the enzymes alanine transaminase, aspartate transaminase and alkaline phosphatase. Individual tests have less value than consideration of the results as a whole.

Biochemical measures of liver function commonly assess:

  • hepatic anion transport - principally, serum bilirubin; less than 5% of serum bilirubin is normally conjugated.

  • abnormal protein synthesis:
    • serum albumin - hypoalbuminaemia in chronic liver injury
    • prothrombin time - may be increased because of failure to absorb fat-soluble vitamin K in cholestasis - Factors II (prothrombin), VII, IX and X are vitamin K dependent; or, from impaired synthesis of coagulation factors - as above plus Factor V and fibrinogen. A raised PT due to cholestasis can generally be corrected by the addition of parenteral vitamin K
    • serum immunoglobulins - usually increased in chronic liver disease. IgM predominantly increased in primary biliary cirrhosis; IgG in chronic autoimmune hepatitis.

  • liver enzyme tests:
    • cytoplasmic and mitochondrial enzymes - raised in hepatocellular damage. ALT is more liver specific than AST and rises more than AST in early hepatocellular injury. AST is raised more in chronic injury.
    • membrane-associated enzymes - alkaline phosphatase and gamma glutamyl transferase are anchored to the biliary canaliculus. They are raised in biliary outflow obstruction rather than hepatocellular damage.

  • miscellaneous - anti-mitochondrial antibodies in primary biliary cirrhosis; increased plasma lipids in cholestasis; serum urea may be reduced in severe hepatic disease

Related pages

Create an account to add page annotations

Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.