Laboratory definitive evidence for a confirmed case requires one of the following:

• detection of HAV nucleic acid
  OR in the absence of HAV vaccination in the preceding 12 weeks:
• detection of anti-HAV IgM
• seroconversion between paired sera tested in the same laboratory (in the absence of recent vaccination).

Samples from confirmed cases should be sent to ESR for genotyping and sequencing (preferably faecal and blood samples).