A novel point-of-care hepatitis C virus (HCV) RNA assay, Xpert HCV, is showing promise in expediting diagnosis and linkage to care, particularly among individuals under active community supervision. The availability of such a test could enable immediate HCV diagnosis for many, including those with acute HCV infection, facilitating more rapid treatment initiation.
Addressing Diagnostic Delays in HCV Care
According to Leah Harvey, MD, MPH, an infectious disease and addiction medicine physician at Brown University, the multistep diagnostic algorithm currently in use often delays HCV diagnosis, especially for marginalized populations. This delay reduces access to curative treatment, particularly for high-risk groups such as people who use drugs and those involved in the carceral system, where substantial barriers exist along the HCV care cascade.
The World Health Organization estimates that approximately 50 million people have chronic HCV infection, with about 1 million new infections occurring annually. Due to the often asymptomatic nature of new HCV infections, diagnosis is frequently delayed, exacerbating the risk of transmission and disease progression.
FDA Approval and Test Performance
In June 2024, the FDA granted marketing authorization to Cepheid for the Xpert HCV test and GeneXpert Xpress System. This marks the first point-of-care HCV test, allowing for a more rapid test-and-treat approach compared to the standard multi-step HCV testing process. The Xpert HCV test detects HCV RNA from a fingertip blood sample and provides results in about an hour, eliminating the need to send samples to a central lab.
The test is intended for adults at risk of or with signs or symptoms of HCV and can be performed in settings operating under a Clinical Laboratory Improvement Amendments (CLIA) Certificate of Waiver, including substance use disorder treatment facilities, correctional facilities, syringe service programs, doctor’s offices, emergency departments, and urgent care clinics.
Study Findings in a Community Supervision Setting
To evaluate the feasibility and clinical performance of the Xpert HCV assay in a nonclinical justice setting, researchers conducted a cross-sectional study of adults under active community supervision (probation or parole) with unknown HCV status or no prior HCV treatment. The study involved 203 participants, with a median age of 38 years, 78.3% male, and 47.7% White. A significant proportion of participants had not completed high school or reported homelessness.
The results indicated that the point-of-care assay had a sensitivity of 96.8% (95% CI, 83.3%-99.9%) and a specificity of 99.4% (95% CI, 96.6%-100%) for HCV RNA detection, using laboratory HCV RNA testing as confirmation. Discrepant RNA results were observed in two participants: one false positive and one false negative.
Further analysis showed that approximately 23.1% of participants with reactive HCV antibody did not have detectable HCV RNA, suggesting spontaneous HCV clearance. Additionally, one participant had negative HCV antibody and detectable HCV RNA, consistent with acute HCV infection.
Limitations and Implications
Investigators noted several limitations, including the single-site study design, the fact that Xpert HCV was not approved for clinical use during the study, and the use of referral for confirmatory testing, which may have caused delays. Despite these limitations, the study underscores the potential of point-of-care HCV RNA assays to facilitate same-day initiation of curative HCV treatment in low-barrier, non-traditional settings, particularly for marginalized populations.
