National case definition: Hepatitis A

Date of last revision: May 2008
Date of last review: May 2008

National notification

Only confirmed cases of disease should be notified.

Type of surveillance

Routine case-by-case notification to the federal level.

Case classification

Confirmed case

Laboratory confirmation of infection in the absence of recent vaccination:

• detection of immunoglobulin M (IgM) antibody to hepatitis A virus (anti-HAV)
• and
• acute clinical illness (see Clinical evidence section)
• or
• an epidemiologic link to a person with laboratory-confirmed hepatitis A infection.

Probable case

Acute clinical illness in a person without laboratory confirmation of infection who is epidemiologically linked to a confirmed case

Laboratory comments

IgM positive results can be a true positive but reflect a remote infection, as HAV-IgM can remain detectable for years after an acute infection because of trailing IgM or the non-disappearance of anti-HAV IgM after recent infection. Acute/recent infection should be confirmed with clinical history symptoms and by repeat titre after 7 to 10 days.

Clinical evidence

Acute clinical illness is characterized by discrete onset of symptoms, including fever, malaise, anorexia, nausea and abdominal pain followed by jaundice or elevated aminotransferase levels within a few days.

ICD code(s)

• ICD-10 code(s)
  • B15.0 Hepatitis A with hepatic coma
  • B15.9 Hepatitis A without hepatic coma [Hepatitis A (acute) (viral) not otherwise specified (NOS)]
• ICD-9/ICD-9CM code(s)
  • 070.0 Viral hepatitis A with hepatic coma
  • 070.1 Viral hepatitis A without mention of hepatic coma

Comments

Probable case definitions are provided as guidelines to assist with case finding and public health management, and are not for national notification purposes.