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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 (IgM) 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) positive, verified by an additional more specific assay.

Case Classification


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


  • Persons who have chronic hepatitis or persons identified as anti-HCV positive should not be reported as having acute viral hepatitis unless they have evidence of an acute illness compatible with viral hepatitis.
  • Up to 20% of acute hepatitis C cases will be anti-HCV negative when reported and will be classified as non-A, non-B hepatitis because some (5%-10%) have not yet seroconverted and others (5%-10%) remain negative even with prolonged follow-up.1
  • Available serologic tests for anti-HCV do not distinguish between acute and chronic or past infection. Thus, other causes of acute hepatitis should be excluded for anti-HCV positive patients who have an acute illness compatible with viral hepatitis.


  1. Kuo G, Choo Q-L, Alter HJ, Gitnick GL, Redeker AG, Purcell RH, Miyamura T, Dienstag JL, Alter MJ, Stevens CE, et al. An Assay for Cirulating Antibodies to a Major Etiologic Virus of Human Non-A, Non-B Hepatitis. Science 1989;244(4902):362-4

Related Case Definition(s)