Liver Function Tests

Question 1

State the 5 serum markers of liver cell damage

Answer 1

Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), bilirubin

Question 2

State the 3 serum markers of synthetic liver function

Answer 2

INR, albumin, glucose

Question 3

Where is AST found?

Answer 3

Liver, heart, skeletal muscles, kidneys, brain

Question 4

What is the typical ratio of AST to ALT in alcoholic hepatitis?

Answer 4

2:1

Question 5

Where is ALT found?

Answer 5

Primarily in the liver

Question 6

What is the typical ratio of AST to ALT in viral hepatitis?

Answer 6

1:1

Question 7

Where is ALP found?

Answer 7

Liver, bones, placenta

Question 8

What are the main causes of a raised ALP?

Answer 8

Cholestasis, bone disease, pregnancy

Question 9

Where is GGT found?

Answer 9

Hepatocytes, biliary cells, kidneys, pancreas

Question 10

What are the main causes of a raised GGT?

Answer 10

Alcoholism, bile duct disease, liver metastases

Question 11

How much albumin does the average adult synthesise per day?

Answer 11

200mg/kg

Question 12

Which clotting factors does the liver synthesise?

Answer 12

Factors V, VII, IX, X, XII, XIII, fibrinogen, prothrombin

Question 13

What is the INR?

Answer 13

Internal normalised ratio: The prothrombin time (PT) standardised for age and population and expressed as a ratio of normal

Question 14

State three causes of deranged clotting other than liver disease

Answer 14

Iatrogenic (e.g. warfarin), hereditary thrombophilia, acquired consumption (e.g. disseminated intravascular coagulation)

Question 15

What is jaundice?

Answer 15

Elevated serum bilirubin causing yellowing of the skin and sclera

Question 16

Describe the normal metabolism of bilirubin

Answer 16

Bilirubin is released from red blood cell breakdown, transported to the liver, conjugated in hepatocytes, secreted into the bile ducts and then GI tract, metabolised into urobilinogen, partially reabsorbed by the kidneys which excrete it as urobilin, and partially converted into stercobilin (the brown pigment in faeces)

Question 17

Describe the laboratory findings in pre-hepatic jaundice

Answer 17

Elevated unconjugated bilirubin, reduced haemoglobin, reduced haptoglobin, raised LDH

Question 18

State two causes of pre-hepatic jaundice

Answer 18

Haemolysis, congestive heart failure

Question 19

Describe the laboratory findings in hepatic jaundice

Answer 19

Elevated unconjugated bilirubin, raised aminotransferases, may be synthetic dysfunction

Question 20

State three causes of post-hepatic jaundice

Answer 20

Biliary tree obstruction (e.g. stones, strictures, inflammation), pancreatic cancer, cholangiocarcinoma

Question 21

Describe the laboratory findings in post-hepatic jaundice

Answer 21

Elevated conjugated bilirubin, elevated urine bilirubin