Liver function test Flashcards
What is the approximate weight of the liver?
Approx 1.5 kg
What are the two blood supplies to the liver?
Art ^ press+high O2, PV low press, low O2
Are liver function tests sensitive or specific?
Not sensitive or specific
What do liver function tests reflect?
Damage rather than function
What is the clinical utility of liver function tests?
Clinically useful and patterns give clues
What is the pathway of bilirubin excretion?
haem–biliverdin–bilirubin–mono then diglucuronide–bile–stool–some reabsorbed as urobilinogen
What condition is associated with an isolated rise in bilirubin?
Gilberts syndrome or haemolysis
Which enzyme is more liver specific, ALT or AST?
Alanine transaminase (ALT)
What happens to ALT levels when hepatocytes die?
Increased when hepatocytes die
What is the ALT level when all hepatocytes are dead?
10,000
In which condition is AST greater than ALT?
Alcoholic liver disease (ALD) or advancing fibrosis
What does Alkaline Phosphatase reflect?
Biliary system, but not specific
What is the significance of Gamma Glutamyltransferase (GGTP)?
Not just in liver, increases by induction not damage
What can cause an increase in GGTP?
Alcohol, obesity, phenytoin, carbamazepine, NAFLD cirrhosis
What is the role of Albumin in the blood?
Important for osmotic effect, carries non-water soluble substances including unconjugated bilirubin
What can cause high levels of Albumin?
Dehydration
What does low Albumin indicate?
Dilution or reduced synthesis
When is Prothrombin time a good marker?
Good marker of synthetic function of the liver, very good in acute liver failure
What does an isolated elevation of bilirubin suggest?
Gilbert’s or haemolysis
What does mild ALT elevation indicate?
Common conditions such as NASH, hepatitis C, ALD including alcoholic hepatitis
What conditions are associated with high ALT levels?
Hepatitis including drug damage
What does GGTP elevation with alkaline phosphatase indicate?
Biliary disease such as stones, pancreatic cancer, primary biliary cholangitis (PBC)
What triggers a ‘liver screen’?
Abnormal liver function tests
What tests are included in a liver screen?
- Hepatitis viruses
- Autoantibodies (ANA, AMA, Anti-SMAb)
- Ferritin
- Caeruloplasmin and Alpha-1-antitrypsin
- Immunoglobulins
- Ultrasound scan and referral
