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.
Current HCV infection should be confirmed by a polymerase chain reaction (PCR) assay for HCV RNA. We recommend that, when ordering HCV serology, clinicians request reflex testing for HCV RNA if HCV serology is positive. This request must be documented on the initial pathology form. 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 or whole blood.
Current criteria for PBS eligibility require evidence of chronic infection documented by repeated HCV antibody positivity and HCV RNA positivity. The traditional clinical definition of chronic HCV infection is duration longer than 6 months. Documentation of seropositivity for longer than 6 months should not be required; a clinical assessment of chronicity is sufficient. The recommended definition for chronic HCV infection has therefore been expanded to include people who have detectable HCV RNA in plasma or whole blood and the absence of clinical features of acute hepatitis (see Special populations- treatment of people with acute HCV infection). A history of injecting drug use or another risk factor for transmission of HCV infection is supportive but not required to make the diagnosis.
The testing protocols described above require venepuncture for collection of whole blood samples. This can present a barrier to care for PWID who have difficult venous access. Finger-prick sample collection can be used to test for hepatitis C. In NSW, a pilot study of dry blood spot (DBS) testing for HCV RNA, using finger-prick sample collection, has been successfully conducted.38 DBS testing can also be used for human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infection. DBS samples need to be sent to a central laboratory for testing, meaning that the result is not available on the day of sample collection. As DBS testing has not yet been approved by the TGA, confirmatory testing using standard diagnostics is required before prescribing DAAs.
There is no point-of-care test for anti-HCV antibodies that is approved for use in Australia. As noted, the Xpert® (Cepheid) point-of-care test for HCV RNA has been approved and uses a finger-prick blood sample (100 uL). The real-time PCR machine can sit onsite and provide a result in less than 60 minutes. This test has been successfully used for screening in high-prevalence clinics (e.g. needle and syringe programs, safe injecting facilities, prison reception centres37 and mental health units). On the basis of these data, the use of point-of-care tests for HCV RNA is being actively evaluated for screening in high-prevalence clinical settings, to increase rates of screening and reduce the rate of loss to follow-up between testing and diagnosis. In 2021, the Commonwealth Government established a national program to scale up hepatitis C point-of-care testing using the Xpert® HCV viral load assay. The program will support access to point-of-care tests for high-prevalence clinics, including staff training, establishment of relationships with NATA-accredited medical testing laboratories and participation in quality assurance programs.
Beyond this national program, however, reimbursement needs to be considered. The current Medicare Benefits Schedule (MBS) reimbursement criteria for HCV RNA testing require documentary evidence of HCV seropositivity. This is a barrier to reimbursement for point-of-care HCV RNA testing in high-prevalence clinics, in the absence of an approved point-of-care test for anti-HCV antibodies and where previous serology results are not readily available. However, evidence suggests that:
i) the rates of HCV seropositivity among PWID in high-prevalence clinical settings in Australia are very high (> 50% among PWID in correctional settings or high-prevalence community settings, such as needle and syringe programs and safe injecting facilities);
ii) many PWID have been previously tested, but the information technology systems do not exist to track results from other providers in a reliable, rapid manner; and iii) the prevalence of hepatitis C (HCV RNA positivity) in PWID remains > 20%,  which is a reasonable threshold for screening tests.
We therefore recommend that, until point-of-care-testing for anti-HCV antibodies becomes available in the community, funding mechanisms should be created to support point-of-care HCV RNA testing without the need for documentation of HCV seropositivity in prescribed high-prevalence clinical settings.
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. Annual testing should be performed using either venepuncture or point-of-care finger-prick testing. 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.