Lecture 12: Liver function test Flashcards
Liver function tests check the levels of certain enzymes and proteins in your blood. Which enzymes are normally checked in liver function tests?
- Alanine transaminase (ALT)
- Aspartate transaminase (AST)
- Alkaline phosphatase (ALP)
- Bilirubin
- Albumin
- Gamma glutamyl transferase
What are the two forms of bilirubin?
Unconjugated bilirubin
Conjugated bilirubin
Name the two aminotransferases used in the Liver function test
- Aspartate aminotransferase (AST)
- Alanine aminotransferase (ALT)
The aminotransferases are markers for what?
Hepato-cellular injury
What is the plasma half life for aspartate aminotransferase (AST)
48 hours
Which is more sensitive and specific for the liver? AST or ALT?
ALT are more sensitive
AST is less sensitive and specific for the liver
What is the plasma half life for alanine aminotransferase (ALT)
18 hours
When is γ – Glutamyl transferase useful in the liver function test
Poor specificity for liver disease but useful to either identify raised ALP of liver origin or to assess chronic alcohol consumption
Describe the relationship between gamma- glutamyl transferase (GGT) and alcohol consumption
- Raised GGT in individuals may be due to induction of the enzyme by the alcohol and/or because of the liver damage
- No relation between level of GGT and amount or duration of alcohol consumption
- Patient with high GGT: ask them to go abstinent from alcohol for 8 weeks and test again
Why might a patient with severe cirrhosis have normal liver function test results
LFTs is normal because the hepatocytes are destroyed.
Describe Caput medusae
Appearance of distended and engorged superficial epigastric veins, which are seen radiating from the umbilicus across the abdomen
It is also a sign of portal hypertension
Describe spider nevi
C collection of small, dilated arterioles (blood vessels) clustered very close to the surface of the skin. The cluster of vessels is web-like, with a central spot and radiating vessels.
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