34
Most Common Abnormalities Indicated by the Test
Dogs and cats—cardiac or skeletal muscle injury when ALT is not increased; liver, cardiac, or
skeletal muscle injury if both ALT and AST are increased.
Horses, cows, and pigs —liver, cardiac, or skeletal muscle injury.
Sample Type and Precautions
Remove plasma or serum promptly from the cells or clot. Hemolyzed specimens should not be used
because AST contamination from red blood cells will occur. EDTA and fluoride/oxalate should not be
used as anticoagulants. If plasma is being collected, use only lithium heparinized samples.
Blood samples should be processed and centrifuged immediately after collection. Even slight
hemolysis can cause marked increases in activity because of high intracellular concentrations of
AST in red blood cells.
Complementary Tests
Aspartate aminotransferase activity is usually determined in conjunction with other tests of liver,
cardiac, or skeletal muscle function or damage.
Reaction Sequence
Blood Urea Nitrogen (BUN)
The catabolism of proteins results in the production of ammonia, which is extremely toxic. Ammonia
is converted to urea in the liver and eliminated from the body by glomerular filtration in the kidneys.
Principal Reason for Performing the Test
As an indicator of renal disease or pathologic conditions that result in bleeding into the
gastrointestinal tract.
Most Common Abnormalities Indicated by the Test
Increased urea—prerenal, postrenal and renal azotemia with decreased glomerular filtration rate;
high-protein diet or bleeding into the gastrointestinal tract.
Decreased urea —decreased protein intake; hepatic insufficiency; diuresis.
Sample Type and Precautions
Remove plasma or serum promptly from the cells or clot. If plasma is being collected, use only
lithium heparinized samples.
Blood should not be drawn for urea determination within 6 hours of a meal. Do not use sodium
fluoride or EDTA as anticoagulant. Samples that contain hemoglobin increase urea nitrogen.
Appendices
Содержание Catalyst One
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