Liver Function tests

Question 1

What is Albumin and why is it measured?

Answer 1

Blood protein involved in transporting molecules around the blood, made in the liver, depressed levels indicate general loss of secretory function (but reduced could also be due to kidney disease - as being lost in the urine)

Question 2

What is GOT(AST) and why is it measured?

Answer 2

Involved in amino acid metabolism in the liver, also found in other tissues (RBC’s) so its presence is not necessarily due to liver damage

Question 3

What is GPT(ALT) and why is it measured?

Answer 3

Also involved in amino acid metabolism, more liver specific than GOT, if high but with normal ALP then liver necrosis, elevated levels could indicate alcohol toxicity, hepatitis, cancer, ratio of GOT/GPT is used to determine the problem

Question 4

What is Alkaline Phosphatase (AP) and why is it measured?

Answer 4

Enzyme that removes phosphate groups from many metabolites, found specifically in ducts leading to the gall bladder, in elevated indicate bile duct obstruction

Question 5

What is the difference between direct bilirubin and total bilirubin and why are they measured?

Answer 5

Direct bilirubin is conjugated bilirubin and total includes unconjugated too, depending on which is elevated it tells you whether its intrahepatic jaundice or pre/extra hepatic jaundice

Question 6

Why is pro thrombin time (INR) measured in LFT’s?

Answer 6

Pro thrombin is produced in the liver, slower clotting time indicates failure of the liver to synthesise and secrete clotting proteins

Question 7

What is gamma glut aryl peptidase (GGT) and why is it measured?

Answer 7

Liver specific enzyme, good indicator specifically of liver damage, but sensitive to minor changes so might be elevated after a big night out