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Complementary Tests
Ammonia may be determined in isolation but more often in conjunction with other tests of hepatic
damage or dysfunction, such as pre- and postprandial bile acids.
Reaction Sequence
Amylase (AMYL)
This section should be read in conjunction with the Lipase (LIPA) section.
The main source of serum amylase is the pancreas, although pathology of the liver and small
intestine may result in significant elevations of this enzyme (above the reference range). Since
amylase is cleared by the kidneys, renal pathology may also result in elevation of amylase
independent of pancreatic disease.
Principal Reason for Performing the Test
As an indicator of pancreatic disease and potential acute pancreatitis.
Most Common Abnormality Indicated by the Test
Acute necrotizing pancreatitis.
Sample Type and Precautions
Remove plasma or serum promptly from the cells or clot. Hemolyzed specimens should not be
used. Do not use oxalate, citrate, or EDTA anticoagulants. If plasma is being collected, use only
lithium heparinized samples.
Blood samples should be taken within one day of the onset of symptoms that suggest acute
pancreatitis.
Complementary Tests
Amylase and lipase are usually determined in conjunction with one another. Evaluation of a
comprehensive chemistry profile that includes electrolytes is generally recommended because
of secondary effects of acute pancreatitis. Specific pancreatic lipase should be considered in
suspected cases of pancreatitis.
Reaction Sequence
Aspartate Aminotransferase (AST)
The enzyme aspartate aminotransferase is present in large amounts in multiple tissues of dogs,
cats, and many other animal species. Hepatocytes, cardiac muscle cells, and skeletal muscle cells
have relatively high concentrations of AST. It is found in the cytoplasm and mitochondria of the cells
and is released into the blood during cell injury. If no increase in ALT is seen in conjunction with an
increased AST in the dog and cat, cardiac or skeletal muscle cell injury is most likely. For increased
AST values with equine, bovine, and porcine samples, liver, cardiac, and skeletal muscle cell injury
must be considered.
Principal Reason for Performing the Test
To investigate damage to liver, cardiac, or skeletal muscle.
Appendices
