Screening for antibodies (IgG) against the virus is the front-line technique for detecting a past or current hepatitis C virus (HCV) infection. For most individuals, the test remains positive throughout their life even after the disease has been cured, but a positive result does not mean the person is protected against a new infection. To diagnose active hepatitis C in an individual with a positive IgG result, an HCV RNA test must be completed. The presence of viral RNA indicates an active infection that requires treatment.
A negative result indicates either no infection or a test performed too soon after exposure to be accurate. For accurate HCV antibody testing, you must typically wait 6 to 12 weeks after infection (longer in immunosuppressed individuals). If the clinical suspicion remains high, the test has to be repeated at a later date. Slightly positive or indeterminate results must be confirmed by the Laboratoire de Santé publique du Québec (LSPQ).