CLINICAL PATHOLOGY - Biochemistry of Liver Disease and Liver Function Flashcards
Which blood sample tubes are used for liver clinical pathology samples?
- Serum tubes
- Lithium heparin tubes
Which parameters are used to investigate liver damage?
- Hepatocellular enzymes
- Biliary enzymes
What are the hepatocellular enzymes used to investigate liver damage?
- Alanine aminotransferase (ALT)
- Aspartate aminotransferase (AST)
- Sorbitol dehydrogenase (SDH)
- Glutamate dehydrogenase (GLDH)
In which animals is alanine aminotransferase (ALT) analysed to detect liver damage?
Small animals
Where is alanine aminotransferase (ALT) found in the body?
Hepatic cytosol
When analysing alanine aminotransferase (ALT) levels, why is it impossible to differentiate between sublethal liver injury and necrosis?
Because alanine aminotransferase has a parallel increase in response to the mass of hepatocyte damage
Where is aspartate aminotransferase (AST) found in the body?
Cytosol and mitochondrial isoenzymes of the hepatocytes, erythrocytes, cardiac muscle cells and skeletal muscle cells
In which animals is sorbitol dehydrogenase (SDH) and glutamate dehydrogenase (GLDH) used to detect liver damage?
Horses and cattle
Where is sorbitol dehydrogenase (SDH) and glutamate dehydrogenase (GLDH) found in the body?
Hepatic cytosol
Why are serum glutamate dehydrogenase (GLDH) levels easier to measure than serum sorbitol dehydrogenase (SDH) levels?
Glutamate dehydrogenase (GLDH) is more stable than sorbitol dehydrogenase (SDH) so doesn’t break down immediately after sampling
What are the biliary enzymes used to investigate liver damage?
- Alkaline phosphatase (ALP)
- Gamma glutamyl transferase (GGT)
Where is alkaline phosphatase (ALP) found in the body?
Biliary epithelial cells
What can cause an increase in alkaline phosphatase (ALP) levels?
- Cholestasis
- Corticocosteroid drug induction
- Bone re-modelling
List the five alkaline phosphatase (ALP) isoenzymes
- Hepatic alkaline phosphatase isoenzymes
- Intestinal alkaline phosphatase isoenzymes
- Bone alkaline phosphatase isoenzymes
- Placental alkaline phosphatase isoenzymes
- Corticosteroid induced alkaline phosphatase isoenzymes
In which animals are corticosteroid induced alkaline phosphatase isoenzymes unique?
Dogs
Why do young animals often have physiological elevation of alkaline phosphatase (ALP)?
Due to rapid bone growth
In which animals is gamma glutamyl transferase (GGT) used to detect liver damage?
Horses, cattle and cats
Where is gamma glutamyl transferase (GGT) found in the body?
- Biliary tree system
- Renal tubules
What can cause elevated serum gamma glutamyl transferase (GGT) levels?
Cholestasis
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?
Because elevated gamma glutamyl transferase (GGT) in the renal tubules would be excreted in the urine and not found in the plasma
What are the two main parameters used to assess liver function?
- Serum bilirubin levels
- Serum bile acid levels
List five additional parameters used to assess liver function
- Albumin
- Cholesterol
- Urea
- Clotting factors
- Glucose
What can cause elevated serum bile acid levels?
- Portosystemic shunts
- Liver failure reducing hepatic functional mass
- Cholestasis causing bile acid reflux
