Aspertate Aminotransferase (AST)

Methodology: 
This AST procedure utilizes a modification of the methodology recommended by the IFCC. In this method, aspartate aminotransferase (AST) catalyzes the transamination of aspartate and α-oxoglutarate, forming L-glutamate and oxalacetate. The oxalacetate is then reduced to L-malate by malate dehydrogenase, while NADH is simultaneously converted to NAD+.The decrease in absorbance due to the consumption of NADH is measured at 340 nm and is proportional to the AST activity in the sample.
Performed: 
Monday - Friday
Reported: 
Within 24 hours
Purpose and principle: 
Serum GOT (glutamic oxalacetic transaminase) is an alternate name for this enzyme which is internationally known as AST (aspartate aminotransferase) by the International Federation of Clinical Chemistry (IFCC) standards.

Serum AST is one of a group of enzymes which catalyzes the interconversion of amino acids and keto acids by transfer of amino groups. Transaminases are widely distributed in body tissues with significant amounts found in the heart and liver. Lesser amounts are also found in skeletal muscles, kidneys, pancreas, spleen, lungs, and brain. Injury to these tissues result in the release of the AST enzyme to general circulation.

Following a myocardial infarction, AST in serum begins to increase within 6 to 8 hours of onset of pain, reaching a peak within 18 to 24 hours and falling to normal by the fourth or fifth day. Serum values may increase to 15 to 20 times normal levels and the increase is roughly proportional to the degree of tissue damage.
Specimen Requirements: 
Type: Peripheral blood

Container/Tube:
  • Serum, gel
  • Plasma, gel

Sample Volume: 0.5mL

Stability (collection to time of analysis/testing):
  • Ambient: 1 day
  • Refrigerated: 4 weeks
  • Frozen: 1 year

Unacceptable Conditions: Moderate-to-gross hemolysis

Specimen Retention Time: 5 days
Reference Values: 
13 - 39 U/L
CPT Code (s): 
84450
Notes: 

UFHPL Test #: 20045

Collection procedure: 
Serum gel tubes should be centrifuged within 2 hours of collection.
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