Investigations of the Liver Flashcards
What is included in LFTs?
Alkaline phosphatase AST (aspartate aminotransferase) ALT (alanine aminotransferase) Bilirubin Albumin
Total protein
GGT (gamma glutamyl transferase)
What does ALT and AST show?
Liver damage/injury
What does bilirubin and albumin show?
Liver function
What tests are used to measure the production of metabolites?
Urea
Plasma
Plasma proteins
What tests are used to measure the clearance of endogenous substances?
Billirubin
Ammonia
Hormones
What tests are used to measure the clearance of exogenous substances?
Drugs
Toxins
Is ALT or AST more specific and why?
ALT
AST is found in red blood cells and muscle
What is a marker used for liver tumours? In what other circumstance may it be raised?
Alpha-fetoprotein
Raised normally in children
What markers would be raised in biliary tract damage?
↑ conjugated bilirubin - due to obstruction
↑ ALP
↑ gammaGT - both due to increased synthesis of enzymes by cells lining the bile canaliculi
What other organs apart from the liver is ALP produced?
Bone
Intestines
Placenta
Isoenzymes can be separated by electrophoresis
Why is gamma glutamyltransferase raised?
structural damage e.g.
Alcohol
Fatty liver
Pancreatic diseases
What is the collection of tests called for biochemical markers of liver fibrosis?
ELF (enhanced liver fibrosis) score
What markers/tests would be abnormal in hepatitis?
↑ unconjugated bilirubin
↑ conjugated bilirubin - impaired excretion
Normal ALP
↑ AST
↑ ALT
Serology tests
Chronic: Anti smooth muscle, anti liver/kidney, anti microsomal, ANA
What specific marker would be abnormal in alcohol abuse?
↑ IgA
What are 5 common disorders of the pancreas?
Acute pancreatitis Chronic pancreatitis Pancreatic insufficiency Cystic Fibrosis Carcinoma of the pancreas
What is the tumour marker for pancreatic cancer?
Ca 199
What tests are used to diagnose acute pancreatitis?
↑ amylase/lipase
Imagine
Clinical history
What tests are used to diagnose chronic pancreatitis?
Imaging Pancreatic function tests: Direct/indirect VitD/Calcium FBC LFTs Glucose Lipid
What is the direct (invasive) pancreatic function test?
Incubation
Stimulation using IV hormones - secretin, CCK
Collect aspirates in the duodenum
Tested for bicarbonate, amylase, tripsin,
What are the indirect (non-invasive) pancreatic function tests?
Testing for elastase in stools
Typsinogen in CF screening
Pacreolauryl and NBT-PABA tests - use florescent markers
What is the gold standard pancreatic function test?
Direct (invasive) test
