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NOTE: A surveillance case definition is a set of uniform criteria used to define a disease for public health surveillance. Surveillance case definitions enable public health officials to classify and count cases consistently across reporting jurisdictions. Surveillance case definitions are not intended to be used by healthcare providers for making a clinical diagnosis or determining how to meet an individual patient’s health needs.

Clinical Description

An acute illness with a) discrete onset of symptoms (such as nausea, vomiting, abdominal pain and diarrhea) and b) jaundice or abnormal serum aminotransferase (ALT) levels

Laboratory Criteria For Diagnosis

  • Serum ALT levels greater than 7 times the upper limit of normal, and Immunoglobulin M antibody to hepatitis A virus (IgM anti-HAV) negative (if done), AND
  • IgM antibody to hepatitis B core antigen (IgM anti-HBc) negative, or if not done, hepatitis B surface antigen (HBsAg) negative, AND
  • Antibody to hepatitis C virus (anti-HCV) screening-test-positive (repeat reactive) verified by an additional more specific assay (e.g., recombinant immunoblot assay [RIBA] for anti-HCV or nucleic acid testing for hepatitis C virus RNA)


  • Anti-HCV screening-test-positive with a signal to cut-off ratio predictive of a true positive as determined for the particular assay (e.g., ≥3.8 for the enzyme immunoassays)

Case Classification


A case that meets the clinical case definition and is laboratory confirmed

Related Case Definition(s)