Liver Function Test

Question 1

Low albumin suggests acute liver damage?

Answer 1

False, albumin is a marker for chronic liver injury. Albumin has a 20 day half-life, hence it won’t show up in acute liver injury

Question 2

Does prothrombin time signify acute or chronic?

Answer 2

Reliable marker for both. PT is usually 10 times INR

Question 3

Most sensitive liver function test

Answer 3

PT as many enzymes in the liver need to work together to induce clotting. If any one of these enzymes is not functional, it affects PT/INR

Question 4

Coagulation factors related to PT

Answer 4

Factors 2,7,9 and 10. Also 1 and 5

Question 5

What changes can be seen in INR/PT in liver failure

Answer 5

INR/PT raises

Question 6

Causes of increased PT other than liver failure

Answer 6

Low vitamin K, haemophilia and anticoagulants

Question 7

Which bilirubin shows up in urine

Answer 7

Conjugated bilirubin

Question 8

Which bilirubin can be found in blood

Answer 8

Both conjugated and unconjugated appear as total bilirubin

Question 9

How can amount of unconjugated bilirubin be calculated

Answer 9

Total bilirubin - Unconjugated bilirubin (in urine)

Question 10

Hepatocyte sensitive test

Answer 10

AST and ALT

Question 11

AST vs ALT

Answer 11

Both are enzymes present in hepatocyte, released upon their death. Used as markers of hepatocyte inflammation.
AST - Seen in periportal hepatocytes, low specificity as also seen in skeletal muscles
ALT - High specificity

Question 12

Are AST and ALT elevated in old injuries

Answer 12

No, they are elevated in recent injuries. Low AST and ALP doesn’t tell us about liver function, whether the liver function is good or damaged and non-functional

Question 13

What can ALP indicate

Answer 13

Cholestasis, pregnancy or bone growth; not very specific

Question 14

What does GGT-Gamma Glutamyl Transferase signify

Answer 14

Cholestasis but not in bone disease. Alcohol can increase GGT

Question 15

How is bilirubin produced and transported to the liver

Answer 15

Breakdown product of haem, transported bound to albumin

Question 16

Urobilinogen vs stercobilinogen

Answer 16

Bilirubin excreted via urine vs faeces

Question 17

Cause of unconjugated hyperbilirubinaemia

Answer 17

Increased bilirubin production -
Extravasation of blood into tissues
Increased haemolysis
Impaired hepatic bilirubin uptake -
Heart failure, porto-systemic shunts, drugs
Impaired bilirubin conjugation - 
Gilbert's syndrome, hyperthyroidism

Question 18

Causes of conjugated hyperbilirubinaemia

Answer 18

Extrahepatic cholestasis (biliary obstruction) -
Cholelithiasis, PSC, Cholangiocarcinoma, pancreatitis
Intrahepatic cholestasis -
Sepsis, Cirrhosis, Hepatitis, Infiltrative disease, Drugs