Aspartate aminotransferase, serum
Clinical Background:
AST is an intracellular enzyme present in both cytoplasm and mitochondria. It is widely distributed throughout the body’s tissues, with the greatest amounts in cardiac muscle, liver, skeletal muscl...
AST is an intracellular enzyme present in both cytoplasm and mitochondria. It is widely distributed throughout the body’s tissues, with the greatest amounts in cardiac muscle, liver, skeletal muscle and the kidneys. It is a key enzyme in gluconeogenesis. AST is used to identify tissue damage e.g. arising from damage to cardiac muscle (typically ischaemic in origin), damage to skeletal muscle (e.g. rhabdomyolysis) and liver cell inflammation or necrosis. The major disadvantage of AST as an indicator of tissue damage is its lack of specificity to any one tissue. Alanine aminotransferase (ALT) is to be preferred as an indicator of liver cell damage. AST present in the plasma is presumed to be derived from the normal turnover of tissue cells; increased quantities are found in tissue damage (particularly hepatic and cardiac and skeletal muscle damage)
Test Details
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Discipline:
Biochemistry
Biochemistry
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Specimen Container Adult:
Serum
Serum
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Specimen Container Paediatric:
Serum
Serum
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Minimum Volume Adult:
1 mL blood
1 mL blood
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Minimum Volume Paediatric:
0.5 mL blood
0.5 mL blood
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Sample Stability:
Unseparated sample: 3 days
Separated sample:
- 4 days at 15-25C
- 7 days at 4ºC
- 3 months at -20C
Unseparated sample: 3 days
Separated sample:
- 4 days at 15-25C
- 7 days at 4ºC
- 3 months at -20C
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Add On Test:
Add-on available up to 7 days
All urgent add ons via telephone on 0191 282 4766, and must be confirmed via email to the appropriate email address
tnu-tr.bloodsciencesadditions@nhs.net (internal)
Read MoreAdd-on available up to 7 days
All urgent add ons via telephone on 0191 282 4766, and must be confirmed via email to the appropriate email address
tnu-tr.bloodsciencesadditions@nhs.net (internal)
tnu-tr.bloodsciencesadditions@nhs.net (external)
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Interpretation:
The most common cause of an isolated increase in AST activity
is alcohol‐related or non‐alcoholic fatty liver disease. For any value, a high
alcohol intake, diabetes and hypertriglyceridaemia (al...Read MoreThe most common cause of an isolated increase in AST activity
is alcohol‐related or non‐alcoholic fatty liver disease. For any value, a high
alcohol intake, diabetes and hypertriglyceridaemia (all of which can cause
fatty liver) should be excluded; if present, these should be managed
appropriately before repeating the test.
For increases ≤2x ULN, and other LFTs normal, repeat in 1–2 months
If repeat value ≤3x ULN, further investigation is required
Values >3x ULN further investigation is appropriate without repeat
testing irrespective of results of other LFTs. -
Reference Ranges:
All ages: 0 - 40 U/L
All ages: 0 - 40 U/L
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Factors Affecting Result:
Haemolysis.
In very rare cases gammopathy, in particular type IgM (Waldenström’s macroglobulinemia), may cause unreliable results.
Isoniazid can cause artificially low AST results at therapeutic co...Read MoreHaemolysis.
In very rare cases gammopathy, in particular type IgM (Waldenström’s macroglobulinemia), may cause unreliable results.
Isoniazid can cause artificially low AST results at therapeutic concentrations.
Cyanokit (hydroxocobalamin) at therapeutic levels causes significantly lower results. -
Other Info:
Plasma- Lithium Heparin also acceptable
Plasma- Lithium Heparin also acceptable
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Routine Contact Name:
Duty Biochemist
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Routine Telephone:
Freeman: 0191 244 8889
RVI: 0191 282 9719Freeman: 0191 244 8889
RVI: 0191 282 9719 -
Routine Email: