An acute illness with a discrete onset of any sign or symptom consistent with acute viral hepatitis (e.g., anorexia, abdominal discomfort, nausea, vomiting), and either a) jaundice, or b) serum alanine aminotransferase (ALT) levels >400 IU/L.
Laboratory criteria for diagnosis
One or more of the following three criteria:
Antibodies to hepatitis C virus (anti-HCV) screening-test-positive with a signal to cut-off ratio predictive
of a true positive as determined for the particular assay as defined by CDC. (URL for the signal
to cut-off ratios: http://www.cdc.gov/ncidod/diseases/hepatitis/c/sc_ratios.htm), OR
Hepatitis C Virus Recombinant Immunoblot Assay (HCV RIBA) positive, OR
Nucleic Acid Test (NAT) for HCV RNA positive
AND, meets the following two criteria:
IgM antibody to hepatitis A virus (IgM anti-HAV) negative, AND
IgM antibody to hepatitis B core antigen (IgM anti-HBc) negative
Case classification:
Confirmed:a case that meets the clinical case definition, is laboratory confirmed, and is not known to have chronic hepatitis C.
Reference:
Division of Viral Hepatitis. Guidelines for Viral Hepatitis Surveillance and Case Management. Centers for Disease Control and Prevention. January 2005.