Blood biochemistry: aspartate aminotransferase (AST)
(AST Serum AST, SAST Glutamic oxalo-acetic transaminase, GOTSerum GOT, SGOT)
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Overview
- Not organ specific, but highest levels in skeletal muscle, cardiac muscle, liver.
Uses
Alone
- Investigation of suspected skeletal muscle damage
 .
- Investigation of suspected cardiac ischemia.
In combination
- Liver damage in combination with:
- Alanine aminotransferase (ALT) .
- Alkaline phosphatase (ALP) .
- Bile acids .
- Muscle damage in combination with CK.
Other points
- ALT is more specific for investigation of liver disease.
Source of test material
- Standard venipuncture .
- For sample tube preference see
 .
Quantity of test material
- 2 ml serum or plasma. Check with laboratory regarding minimum recommended volume for single test or in combination with other tests.
Quality control
Precautions
Timing of test
- Fast animal for 8 h before sampling to prevent sample lipemia.
Sample storage
- Refrigerate prior to despatch.
- Avoid excessive temperatures.
Sample transport
- Standard postal times adequate.
- Package according to mailing regulations .
- Separate serum/plasma before despatch.
Methodologies
- Method and reference interval may vary between laboratories.
- Enzymatic methods commonly used.
Availability
Technique (intrinsic) limitations
- Results only significant when interpreted in conjunction with other laboratory tests and clinical findings.
Normal (reference) values
- Reference interval may vary between methods/laboratories. Example of reference interval: 23-66 iu/l.
- <100 iu/l probably not pathological.
Abnormal values
Increased [AST] - It may be difficult to differentiate whether modest increases in AST are associated with cardiac or skeletal muscle origin.
- Skeletal muscle damage .
- Cardiac ischemia:
- Bacterial endocarditis .
- Aortic thrombosis.
- Myocardial infarction.
- Liver damage/necrosis .
Errors and Artifacts
False increase - Hemolysis.
- Lipemia.
- Prolonged contact of serum with cells/clot even when hemolysis is not observed.
Publications
Other sources of information
- Ettinger S J & Feldman E C (eds) (2000) Textbook of Veterinary Internal Medicine. 5th edn. Philadelphia: W B Saunders & Co.
- Kaneko J J, Harvey J W & Brass M L (eds) (1997) Clinical Biochemistry of Domestic Animals. 5th edn. Boston: Academic Press.
- Duncan J R, Prasse K W & Mahaffey E A (1994) Veterinary Laboratory Medicine. Clinical Pathology. 3rd edn. Iowa: Iowa University Press.
Vetstream contributor(s)
- Dr Kathleen P Freeman DVM MS PhD , Idexx Laboratories, PO Box 4, Wetherby, West Yorkshire LS22 4ZR, UK.
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