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Hepatitis A - Management
How do I interpret assay results?

  • Hepatitis A virus immunoglobulin M (HAV-IgM)
    • If the test result is negative:
      • Recent hepatitis A infection is unlikely.
      • Repeat the test 1 week later if the person is in the first 7–10 days of symptoms, to exclude a false-negative result.
    • If the test result is reactive:
      • Acute hepatitis A infection is likely.
      • HAV-IgM is detectable about 3 weeks after exposure, increases in titre over 4–6 weeks, then declines to non-detectable levels (generally within 6–12 months of infection).
      • Interpret a reactive result with caution in elderly people, who are more likely to have had hepatitis A in childhood (false-positive IgM results are more common in elderly people).
    • If the test result is reactive but probable non-specific IgM reactivity:
      • Repeat the test.
  • Hepatitis A virus immunoglobulin G (HAV-IgG)
    • HAV-IgG is detectable 5–10 days after the onset of symptoms and persists, conferring lifelong immunity.
    • The presence of HAV-IgG indicates current or past infection, or immunity from previous vaccination.

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