LFTs Flashcards
What is ALT?
Alanine aminotransferase
What is AST?
Aspartate aminotransferase
What is ALP?
Alkaline phosphate
What is GGT or Gamma GT?
Gamma glutamyl transferase
Which liver function markers indicate inflammation and why?
ALT and AST (aminotransferases)
Liver enzymes in hepatocytes which leak into the blood stream when liver cells are damaged.
High in hepatitis
Which amino transferase is more specific to the liver?
ALT as AST can be raised in muscle damage
Where is ALP found?
Enzyme mainly in the bile ducts of the liver
What does and increase in ALP suggest regarding the liver?
Obstructive or cholestatic disease
ALP can also be raised in bone disease. What additional enzyme can be tested along with ALP to check the problem is liver related?
GGT will also be raised with ALP if its a liver problem.
What can cause a low albumin?
Chronic liver disease- especially if it is getting worse.
Proetin deficiency
Which clotting factors are produced in the liver?
Fibrinogen, Factor 2 (prothrombin), 7, 9 and 10.
ANd protein C, S and antithrombin which aid fibrinolysis
What causes pre-hepatic jaundice?
Excessive RBC breakdown which overwhelms the livers ability to conjugate bilirubin => Unconjegated hyperbilirubinaemia.
Haemolytic anaemia, Gilbert’s syndrome
What causes hepatocellular jaundice?
Liver dysfunction.
Liver loses ability to conjugate bilirubin. Cirrhosis can compress the intrahepatic portions of the biliary tree causing obstruction => Mixed (conjugated and unconjugated bilirubin in the blood.
Alcoholic liver disease, Viral hepatitis, Medication, autoimmune hepatitis, HCC, Primary sclerosing cholangitis
What causes post hepatic jaundice?
Obstruction of biliary drainage. Bilirubin is conjugated in the liver but cannot get into gut and spills into blood => conjugated hyperbilirubinaemia. Gall stones (intraluminal) Wall causes (cholangiocarcinoma, strictures) Outside of the wall compression (pancreatic cancer or abdo mass)
What colour is conjugated bilirubin (soluble) in the urine?
Brown- so an excess of conjugated billirubin (post hepatic or hepatocellular) makes the urine very dark brown (coca cola)
What is albumin?
A marker of liver synthesising function
What is the half life of ALP?
A week. May lag behind disease and continue after treatment.
What is the classic faeces/rine picture for cholestatic disease?
Pale faeces and dark urine.
How is bilirubin transported in the blood?
Bound to albumin
Which clotting factors does the liver synthesise?
Fibrinogen (factor 1)
Prothrombin (factor 2)
Factor 5, 7, 9, 10, 12 and 13.
What does PT time measure?
Time it takes for prothrombin to be converted to thrombin.
What does an elevated PT suggest?
Reduced synthetic function of the liver. Not necessarily pro haemorrage as the liver also synthesis protein C, S and antithrombin and these will also be reduced in poor liver function.
What causes, excluding liver function can prolong the prothrombin time?
Drugs (warfrin)
Bile malabsorbtion causing relative Vit K deficiency
Consumptive (sepsis)/congenital (Haemophillia) coaguopathies
The reference ranges for LFTs change around the country. Can people have liver disease and normal LFTs?
Yes- all in the history and presentation
