investigations

Last reviewed 08/2021

  • liver function tests:
    • serum alkaline phosphatase is markedly raised in more than 95% of cases, and usually from an early stage
      • typically the serum ALP will be raised up to three or four times normal (1)
    • mild elevation of aminotransferases alanine aminotransferase [ALT] or aspartate aminotransferase [AST] - raised later rather than early
    • increased levels of immunoglobulins – mainly IgM
    • late features
      • serum bilirubin is raised in most cases
      • alterations in prothrombin and serum albumin
  • immunology:
    • anti-mitochondrial antibodies (specifically to the M2 antigen) occur in 95% of cases - these may rarely be seen in a small proportion of patients with chronic active hepatitis or cryptogenic cirrhosis
    • smooth muscle antibodies in 50%
    • antinuclear factor in 20%
    • IgM is raised in more than 80% of cases
    • negative ANCA
  • increased cholesterol levels
  • liver biopsy
    • confirms the diagnosis but not mandatory to make the diagnosis
    • useful for assessment of the activity and staging of the disease
    • stainable levels of copper may approach that seen in Wilson's disease as a result of the cholestasis.
  • imaging
    • MRI or endoscopic retrograde cholangiography – to exclude primary sclerosing cholangitis or other disorders that might lead to chronic cholestasis
    • transient elastography - to evaluate the degree of liver fibrosis,
  • thyroid function tests often reveal a lowered T4.

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