LFTs Flashcards
what are aminotransferases (AST, ALT) associated with
hepatocellular damage
what is more specific for liver damage ALT or AST
ALT
what is the ratio of AST:ALT useful for
DDx
raised aminotransferases
AST:ALT is 1
associated with ischaemia
1 CCF
2 ischaemic necrosis
3 hepatitis
raised aminotransferases
AST:ALT is >2.5
associated with alcohol
e.g. alcoholic hepatitis
raised aminotransferases
AST:ALT is <1
high rise in ALT (which is most specific for hepatocellular damage)
may indicate paracetamol overdose with hepatocellular necrosis
viral hepatitis may also cause this
what do raised ALP and GGT normally indicate
cholestasis (blockage with gallstone)
what is ALP associated with
cholestasis and malignant hepatic infiltration
it is also a marker of rapid bone turnover and extensive bone metastasis
what is GGP associated with
alcohol ingestion
non-specific marker of hepatocellular damage
very sharp rise with biliary and hepatic obstruction
what is indicated if AST is >20times normal range
acute viral hepatitis
toxic hepatitis
ischaemic hepatitis (CCF)
what is indicated if AST is 10-20time normal
alcoholic cirrhosis infectious mononucleosis (glandular fever)
what is indicated if AST is 5-10times normal
liver (chronic hepatitis)
what do very high levels of ALT indicate
hepatocellular injury
1 viral hepatitis
2 toxic hepatitis
3 ischaemic hepatitis
what do moderately raised levels of ALT indicate
infection (infectious mononucleosis - glandular fever)
liver (chronic hepatitis)
what are slightly raised levels of ALT suggestive of?
often suggestive of AST:ALT >2.5
which is commonly alcoholic liver disease (hepatitis or cirrhosis)
what is seen first in biliary obstruction (raised ALP or raised bilirubin)
raised ALP
what are causes of raised ALP
pathological liver bone non-pathological pregnancy blood type O + B
what causes raised ALP in pregnancy
comes from placenta
what causes raised ALP in blood types O + B
usually due to a small meal, ALP is released from the small intestine
what are causes of raised ALP (liver)
usually indicates cholestasis or obstruction
what are causes of raised ALP (bone)
osteomalacia
bone metastasis
pagets
what produces GGT
renal tubules, liver, biliary tract, pancreas,
what is the benefit of GGT
sensitive marker of hepatocellular damage (more so than ALP + AST) but much less specific
what are causes of raised GGT
liver (hepatocellular damage)
pancreatitis
what are causes of a rapid increase in GGT
obstructive jaundice
what is LDH (LD1 and LD2) commonly found in
heart, RBCs, kidneys
what is LDH (LD3) commonly found in
lungs
what is LDH (LD4 and LD5) commonly found in
liver and skeletal muscle
