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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

Most hepatitis C virus (HCV)-infected persons are asymptomatic. However, many have chronic liver disease, which can range from mild to severe including cirrhosis and liver cancer.

Laboratory Criteria For Diagnosis

  • Anti-HCV positive (repeat reactive) by enzyme immunoassay (EIA), verified by an additional more specific assay (e.g., recombinant immunoblot assay [RIBA] for anti-HCV or nucleic acid testing for HCV ribonucleic acid [RNA]), OR
  • HCV RIBA positive, OR
  • Nucleic acid test for HCV RNA positive, OR
  • Report of HCV genotype, OR
  • 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 EIA) as determined and posted by CDC.

Case Classification


A case that is anti-HCV positive (repeat reactive) by EIA and has alanine aminotranferase (ALT or SGPT) values above the upper limit of normal, but the anti-HCV EIA result has not been verified by an additional more specific assay or the signal to cutoff ratio is unknown.


A case that is laboratory confirmed and that does not meet the case definition for acute hepatitis C.

Related Case Definition(s)