Laboratory Assessment of Liver Function

Describe the laboratory assessment of liver function

Synthetic Function

Measures of synthetic function include:

  • Albumin
    Main plasma protein.
    • Normal range 28-58g.L-1
    • Half-life ~20 days
    • Important in:
      • Maintenance of plasma oncotic pressure
      • Binding
        • Calcium
        • Drugs
    • Decreased in liver dysfunction and malnutrition
  • Coagulation Assays
    Clotting factors are produced by the liver. Hepatic impairment may result in reduced production and abnormality of clotting assays, although functional clotting function may be normal (as pro-coagulant proteins are affected to a similar extent).
    • INR
      Test of the extrinsic pathway.
    • APTT
      Test of intrinsic pathway.

Metabolic Function

Transaminases are released when liver parenchyma is damaged, and are used to evaluate metabolic function:

  • ALT
    Normal range < 54 U.L-1.
  • AST
    Normal range < 35 U.L-1.

Obstructive Tests

  • ALP (Alkaline Phosphatase)
    Enzyme involved in dephosphorylation of many compounds. ALP is found in all cells, but particularly in the liver, bile duct, bone, kidney, and placenta.
    • Normal range is 30-120 U.L-1
  • GGT
    Enzyme found in biliary duct.
    • Normal range:
      • Males: 11-50 U.L-1
      • Females: 7-30 U.L-1
  • Bilirubin
    Byproduct of haemaglobin metabolism. May be measured as total, or as conjugated and unconjugated bilirubin.

References

Diaz, A. Outline the clinical laboratory assessment of liver function. Primary SAQs.

Last updated 2017-09-20

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