Hepatitis C virus

Hepatitis C virus

Infection: Hepatitis C virus; HCV; hep C

Brief description:
  • Most new infectious in NZ are associated with intravenous drug use.
  • Other risk factors include blood transfusion in NZ prior to 1992, migration or healthcare received from a high incidence country, incarceration, tattooing in non-licensed premises.
  • Most infections are asymptomatic.
Did you know?

HCV is now highly curable due to potent new treatments. However, reinfection is possible, as immunity does not develop.

Who should I test?

Test for HCV in people with risk factors or abnormal liver tests.

Test of choice:

Depends on whether already known to have a positive antibody

Serology (HCV antibody) is the first line test for diagnosis in people who have not tested positive before. It indicates infection at some point in time.

  • Excellent sensitivity – a negative test excludes hep C infection (unless exposure has occurred within the last few months).
  • Excellent specificity – a positive result confirms infection with HCV at some stage, but does not necessarily mean the patient has active infection.

HCV core antigen or HCV RNA (HCV PCR/viral load) give the same information and distinguish resolved from active infection

  • In our laboratory, HCV core antigen is added on automatically to patient samples that test positive for HCV antibody, to determine active infection status.
  • Excellent sensitivity – a negative antigen result excludes active infection in almost all people (HCV core antigen may be negative in people with lower viral loads, however this is uncommon). The combination of a positive HCV antibody with a negative core antigen/RNA indicates cleared/past infection.
  • Excellent specificity – a positive result confirms active infection.
  • HCV RNA also used to confirm cure from virus 12 weeks after completing treatment.
Tests to avoid/specialist tests:

HCV antibody testing in people who have tested positive in the past.

  • HCV antibody remains positive life-long, even with clearance of the virus. Repeat testing does not give any information as to whether the person has active infection or not.
  • Request HCV RNA or HCV core antigen if determination of active infection status is required in those who have had a positive antibody in the past.


  • Because current treatments are effective on all genotypes this is no longer routinely required.