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Aspartate Aminotransferase; AST

Pseudonyms: Systematic name L‐aspartate:2‐oxoglutarate aminotransferase (EC2.6.1.1); also oxaloacetate aminotransferase, glutamate oxaloacetate aminotransferase; formerly known as aspartate transaminase and SGOT.

General information

Collection container:

Adults - serum (with gel separator, 4.9mL Sarstedt brown top).

Paediatrics - lithium heparin plasma (1.2mL Sarstedt orange top tube).

Type and volume of sample: The tubes should be thoroughly mixed before transport to the lab. The test may be added to a profile without provision of a separate specimen provided a full tube has been received. This test is NOT included in the standard liver function profile.

Specimen transport/special precautions: N/A

Laboratory information

Method principle:

Aspartate + 2‐oxoglutarate → (AST) → oxaloacetate + glutamate

Oxaloacetate + NADH + H+ → (MD) → malate + NAD+

Pyridoxine 5'‐phosphate is a coenzyme for the AST reaction; its addition to the reaction mixture ensures that all the apoenzyme is catalytically active and measured.

Biological reference ranges:

Up to 14D 20-98 IU/L
Up to 3yrs 16-69 IU/L
>3 years Male <50 IU/L
Female <35 IU/L


Turnaround times: Results are available within 1 hour (urgent - for paeds please phone lab in advance of sampling) or 4 hours (routine).

Clinical information

Used in similar fashion to ALT i.e. to detect hepatotoxicity. However, there is less hepatic specificity to AST compared with ALT. The ALT/AST ratio is sometimes used to implicate alcoholic liver disease in symptomatic individuals.

Tissue specificity: the relative activity of AST in various tissues (where plasma = 1) is: liver 2850x; kidneys 1200x; heart 450x; skeletal muscle 300x.

 

(Last reviewed 25th June 2017)