Newcastle Laboratories

Alanine aminotransferase, serum

Clinical Background:

ALT is an intracellular cytoplasmic enzyme. It is widely distributed throughout the body’s tissues, with the greatest amounts in liver and the kidneys. It is a key enzyme in gluconeogenesis. ALT pr...

ALT is an intracellular cytoplasmic enzyme. It is widely distributed throughout the body’s tissues, with the greatest amounts in liver and the kidneys. It is a key enzyme in gluconeogenesis. ALT 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 cell damage).

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Test Details

  • Discipline:

    Biochemistry

    Biochemistry

  • Specimen Container Adult:

    Serum-SST

    Serum-SST

  • Specimen Container Paediatric:

    Serum-Plain tube

    Serum-Plain tube

  • Minimum Volume Adult:

    1 mL blood

    1 mL blood

  • Minimum Volume Paediatric:

    0.5 mL blood

    0.5 mL blood

  • Sample Stability:

    Unseparated: 4 days.

    Separated:

    7 days at 4ºC

    3 days at 15-25C

    Unseparated: 4 days.

    Separated:

    7 days at 4ºC

    3 days at 15-25C

  • Interpretation:

    ALT is used to identify liver damage e.g. arising from liver cell
    inflammation or necrosis, significant increases in its plasma
    activity are rarely seen other than in liver disease. It may be mea...

    ALT is used to identify liver damage e.g. arising from liver cell
    inflammation or necrosis, significant increases in its plasma
    activity are rarely seen other than in liver disease. It may be measured
    both in patients with clinical features suggestive of liver disease and in
    patients at risk of developing liver disease.
    This latter category includes individuals with:
    • a high alcohol intake
    • a history of known or possible exposure to hepatitis viruses
    • obesity or diabetes
    • a history of consumption of potentially hepatotoxic drugs
    • a family history of liver disease.
    ALT is measured as an index of liver damage for which it is
    more specific than aspartate aminotransferase (AST). Values >20x the
    upper limit of normal may occur with severe liver damage. Smaller
    increments (usually <5xULN) may occur in cholestasis, due to secondary
    damage to hepatocytes.
    In established liver disease, a falling ALT value usually reflects
    decreasing cell damage, but may occasionally be a consequence of such
    massive destruction that, with clearance of the enzyme, even continuing
    damage does not maintain high levels.
    In the context of liver disease, measuring both ALT and AST provides
    little additional information over that provided by measuring either one.
    There are two exceptions: in fatty liver disease, an activity ratio AST/ALT
    of >2 suggests alcohol as a cause; a ratio of ≤1 is suggestive of a non‐
    alcoholic cause.

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  • Reference Ranges:

    All ages: 0 - 40 U/L

    All ages: 0 - 40 U/L

  • Factors Affecting Result:

    Haemolysis.
    In very rare cases gammopathy, in particular type IgM (Waldenström’s macroglobulinemia), may cause unreliable results

    Haemolysis.
    In very rare cases gammopathy, in particular type IgM (Waldenström’s macroglobulinemia), may cause unreliable results

  • Other Info:

    Plasma- Lithium Heparin also acceptable

    Plasma- Lithium Heparin also acceptable

  • Routine Contact Name:

    Duty Biochemist

  • Routine Telephone:

    Freeman: 0191 244 8889
    RVI: 0191 282 9719

    Freeman: 0191 244 8889
    RVI: 0191 282 9719

  • Routine Email:

    - For external users: TNU-Tr.duty.biochemist@nhs.net

    - For Trust users: DutyBiochemist@nuth.nhs.uk

Availability:

All times
All sites

Turn Around:

Urgent: within 1 hour

Non-urgent: within 4 hours

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