Screening and diagnosis

Transmission of HCV infection is associated with identifiable risk factors (Box 2), and most diagnoses result from screening of at-risk populations. All individuals with a risk factor for HCV infection should be tested. The appropriate screening test for HCV is serology (HCV antibodies), which indicates exposure to HCV, either current or past infection.

Box 2 Populations to consider for a hepatitis C virus (HCV) screening test

  • People who inject drugs or who have ever injected drugs
  • People in custodial settings
  • People with tattoos or body piercing
  • People who received a blood transfusion or organ transplant before 1990
  • People with coagulation disorders who received blood products or plasma-derived clotting factor treatment products before 1993
  • Children born to HCV-infected mothers
  • People infected with human immunodeficiency virus (HIV) or hepatitis B virus
  • Sexual partners of an HCV-infected person (individuals at higher risk of sexual transmission include men who have sex with men and people with HCV–HIV coinfection)
  • People with evidence of liver disease (persistently elevated alanine aminotransferase level)
  • People who have had a needle-stick injury
  • Migrants from high-prevalence regions (Egypt, Pakistan, Mediterranean and Eastern Europe, Africa and Asia)

Current HCV infection should be confirmed by a polymerase chain reaction (PCR) assay for HCV RNA. About 25% of acute HCV infections will clear spontaneously within 6 months; these individuals continue to be HCV antibody-positive but do not have detectable HCV RNA in plasma. Criteria for PBS eligibility require evidence of chronic infection documented by repeated HCV antibody positivity and HCV RNA positivity. The clinical definition of chronic HCV infection is duration longer than 6 months.

Annual HCV serological testing is recommended for seronegative individuals with ongoing risk factors for HCV transmission. For individuals who are seropositive but have undetectable HCV RNA (indicating past infection), annual HCV RNA testing is recommended only in the setting of ongoing risk factors for HCV transmission. Patients with prior positive HCV serological test results do not require repeated serological testing, as most people will have detectable HCV antibodies for life regardless of antiviral treatment.