Interpretation of Liver Function Tests Flashcards
Where is ALT located?
Liver
Where is AST predominantly found?
Found in many tissues:
- Liver
- Muscle Tissues
- Heart
Where is ALP located?
Biliary System
Bones
Placenta
Where is GGT located?
Biliary System
What do liver function tests tell you?
They don’t tell you anything about function of the liver
Instead, elevation of enzymes can indicate damage to the liver or biliary system or both
Think of them as liver ‘damage’ tests
When is ALT raised?
Raised in:
Liver damage - so ALT leaks out into blood from hepatocytes
Highly specific for liver damage
When is AST raised?
- Liver damage
- Muscle damage - rhabdomyolysis
- Myocardial Infarctions
When is ALP raised?
Cholestasis - reduction or blockage in flow of bile through liver
Increased bone breakdown disorders - Paget’s disease of the bone, bony mets, renal osteodystrophy
Pregnancy
When is GGT raised?
Cholestasis
Alcohol use
For liver damage what enzymes are raised in what ratio?
ALT and AST both increased, with ALT being more increased than AST
If AST is raised but not ALT, what differentials are you thinking?
Think something else not to do with liver like bones or cardiac muscle
If AST:ALT ratio is >2 what is this indicative of?
Alcoholic liver disease
If ALT or AST is >1000 IU/L, what is this indicative of?
Ischaemic hepatitis
Paracetamol overdose
Severe viral hepatitis
Severe autoimmune hepatitis
What enzyme does alcohol raise?
GGT
Sudden increase in ALP and GGT, what is this indicative of?
Hepatocellular carcinoma
