CLINICAL PATHOLOGY - Biochemistry of Liver Disease and Liver Function

Question 1

Which blood sample tubes are used for liver clinical pathology samples?

Answer 1

• Serum tubes
• Lithium heparin tubes

Question 2

Which parameters are used to investigate liver damage?

Answer 2

• Hepatocellular enzymes
• Biliary enzymes

Question 3

What are the hepatocellular enzymes used to investigate liver damage?

Answer 3

• Alanine aminotransferase (ALT)
• Aspartate aminotransferase (AST)
• Sorbitol dehydrogenase (SDH)
• Glutamate dehydrogenase (GLDH)

Question 4

In which animals is alanine aminotransferase (ALT) analysed to detect liver damage?

Answer 4

Small animals

Question 5

Where is alanine aminotransferase (ALT) found in the body?

Answer 5

Hepatic cytosol

Question 6

When analysing alanine aminotransferase (ALT) levels, why is it impossible to differentiate between sublethal liver injury and necrosis?

Answer 6

Because alanine aminotransferase has a parallel increase in response to the mass of hepatocyte damage

Question 7

Where is aspartate aminotransferase (AST) found in the body?

Answer 7

Cytosol and mitochondrial isoenzymes of the hepatocytes, erythrocytes, cardiac muscle cells and skeletal muscle cells

Question 8

In which animals is sorbitol dehydrogenase (SDH) and glutamate dehydrogenase (GLDH) used to detect liver damage?

Answer 8

Horses and cattle

Question 9

Where is sorbitol dehydrogenase (SDH) and glutamate dehydrogenase (GLDH) found in the body?

Answer 9

Hepatic cytosol

Question 10

Why are serum glutamate dehydrogenase (GLDH) levels easier to measure than serum sorbitol dehydrogenase (SDH) levels?

Answer 10

Glutamate dehydrogenase (GLDH) is more stable than sorbitol dehydrogenase (SDH) so doesn’t break down immediately after sampling

Question 11

What are the biliary enzymes used to investigate liver damage?

Answer 11

• Alkaline phosphatase (ALP)
• Gamma glutamyl transferase (GGT)

Question 12

Where is alkaline phosphatase (ALP) found in the body?

Answer 12

Biliary epithelial cells

Question 13

What can cause an increase in alkaline phosphatase (ALP) levels?

Answer 13

• Cholestasis
• Corticocosteroid drug induction
• Bone re-modelling

Question 14

List the five alkaline phosphatase (ALP) isoenzymes

Answer 14

• Hepatic alkaline phosphatase isoenzymes
• Intestinal alkaline phosphatase isoenzymes
• Bone alkaline phosphatase isoenzymes
• Placental alkaline phosphatase isoenzymes
• Corticosteroid induced alkaline phosphatase isoenzymes

Question 15

In which animals are corticosteroid induced alkaline phosphatase isoenzymes unique?

Answer 15

Dogs

Question 16

Why do young animals often have physiological elevation of alkaline phosphatase (ALP)?

Answer 16

Due to rapid bone growth

Question 17

In which animals is gamma glutamyl transferase (GGT) used to detect liver damage?

Answer 17

Horses, cattle and cats

Question 18

Where is gamma glutamyl transferase (GGT) found in the body?

Answer 18

• Biliary tree system
• Renal tubules

Question 19

What can cause elevated serum gamma glutamyl transferase (GGT) levels?

Answer 19

Cholestasis

Question 20

Gamma glutamyl transferase (GGT) is found in the renal tubules as well as the biliary tree system. Why does this not impact the analysis of serum gamma glutamyl transferase (GGT) levels during a clinical investigation for liver disease?

Answer 20

Because elevated gamma glutamyl transferase (GGT) in the renal tubules would be excreted in the urine and not found in the plasma

Question 21

What are the two main parameters used to assess liver function?

Answer 21

• Serum bilirubin levels
• Serum bile acid levels

Question 22

List five additional parameters used to assess liver function

Answer 22

• Albumin
• Cholesterol
• Urea
• Clotting factors
• Glucose

Question 23

What can cause elevated serum bile acid levels?

Answer 23

• Portosystemic shunts
• Liver failure reducing hepatic functional mass
• Cholestasis causing bile acid reflux