Point-of-Care Hepatitis C Test May Expedite Diagnosis

Leah Harvey, MD, MPH Credit: Brown University

This article originally appeared on our sister site, HCPLive.

Testing is key to getting people with hepatitis C into the continuum of care. And, getting people tested can be challenging, especially as the virus can be asymptomatic. However, new research is calling attention to the potential utility of a point-of-care hepatitis C virus (HCV) RNA assay (Xpert HCV) in a nontraditional, nonclinical setting for facilitating more rapid diagnosis and linkage to care among individuals under active community supervision.¹

Study results showed that the availability of a point-of-care HCV RNA assay for clinical use among individuals under active probation or parole would have enabled 30 people, including 2 with acute HCV infection, to receive an immediate HCV diagnosis, highlighting the feasibility and clinical performance of Xpert HCV in this setting.¹

“Progress toward HCV elimination in the US has been stalled by reliance on a multistep diagnostic algorithm to confirm viremia, reducing access to curative treatment,” Leah Harvey, MD, MPH, an infectious disease and addiction medicine physician and an assistant professor in the division of infectious diseases at the Warren Alpert School of Medicine at Brown University, and colleagues wrote.¹ “In populations at highest risk of infection—including people who use drugs and those involved in the carceral system—treatment is often inaccessible owing to substantial barriers along the HCV care cascade.”

According to the World Health Organization, an estimated 50 million people have chronic HCV infection, with about 1 million new infections occurring per year. Since new HCV infections are often asymptomatic, diagnosis typically does not occur when the infection is recent.² Risk of infection and delayed diagnosis/treatment are especially prevalent among people who use drugs and those involved in the carceral system.¹

On June 27, 2024, the FDA granted marketing authorization to Cepheid for the Xpert HCV test and GeneXpert Xpress System, the first point-of-care HCV test allowing for a more rapid test-and-treat approach than the standard multi-step HCV testing process. Rather than requiring a sample to be sent to a central lab for testing, the Xpert HCV detects HCV RNA and provides results in about an hour using a blood sample from the fingertip.³

The test, which is intended for adults at risk of or with signs or symptoms of HCV, can be performed in settings operating under a Clinical Laboratory Improvement Amendments (CLIA) Certificate of Waiver, such as certain substance use disorder treatment facilities; correctional facilities; syringe service programs; doctor’s offices; emergency departments; and urgent care clinics.³ However, its clinical use in a community supervision setting has not yet been explored.¹

To examine the feasibility and clinical performance of a point-of-care HCV RNA assay (Xpert HCV) in a nonclinical justice setting, investigators conducted a cross-sectional study of English-speaking adults ≥ 18 years of age under active community supervision status (probation or parole) with unknown HCV status or no self-reported prior HCV treatment.¹

Among 482 participants enrolled in a larger HCV antibody study assessing HCV testing and linkage to care for this population, a convenience sample of 203 participants underwent point-of-care HCV RNA testing and were included in the present analysis. Among this group, the median age was 38 (Interquartile range, 31-48.5) years, 78.3% of participants were male, and 47.7% were White. Investigators pointed out approximately ⅓ of participants had not completed high school or reported homelessness.¹

In total, 190 (94%) participants had valid laboratory HCV RNA results. Missing data were due to inconclusive results (n = 1), unavailable results (n = 5), or testing was not performed (n = 7).¹

Using laboratory HCV RNA testing for confirmation, investigators noted the sensitivity of the point-of-care assay for HCV RNA detection was 96.8% (95% CI, 83.3%-99.9%), and the specificity was 99.4% (95% CI, 96.6%-100%). They also pointed out discrepant RNA results in 2 participants: the first was interpreted as a false positive point-of-care HCV RNA (had reactive HCV antibody, POC HCV RNA detected, laboratory HCV RNA not detected) and the second was interpreted as a false negative point-of-care HCV RNA (nonreactive HCV antibody, POC HCV RNA not detected, laboratory HCV RNA detected).¹

Further analysis revealed approximately 9 of 39 participants (23.1%) with reactive HCV antibody did not have detectable HCV RNA (point-of-care and laboratory), indicative of spontaneous HCV clearance. Additionally, a single participant had negative HCV antibody and detectable HCV RNA (point-of-care and laboratory) consistent with acute HCV infection.¹

Investigators outlined multiple limitations to these findings, including the potential lack of generalizability to other settings due to the single-site study design; the fact that Xpert HCV was not approved for clinical use when the study was conducted; and the use of referral to complete laboratory-based confirmatory testing, which may have led to delays.¹

“Multistep diagnostic algorithms cause unnecessary delay in HCV diagnosis, particularly for marginalized populations. The recent approval of the first POC HCV RNA assay in the US will facilitate same-day initiation of curative HCV treatment in low-barrier, nontraditional settings,” investigators concluded.¹

References

1. Harvey L, Jacka B, Bazerman L, et al. Feasibility and Performance of a Point-of-Care Hepatitis C RNA Assay in a Community Supervision Cohort. JAMA Netw Open. doi:10.1001/jamanetworkopen.2024.38222

2. World Health Organization. Hepatitis C. Newsroom. April 9, 2024. Accessed October 10, 2024. https://www.who.int/news-room/fact-sheets/detail/hepatitis-c

3. Brooks, A. FDA Grants Marketing Authorization to Xpert HCV, First Point-of-Care Hepatitis C RNA Test. HCPLive. June 27, 2024. Accessed October 10, 2024. https://www.hcplive.com/view/fda-grants-marketing-authorization-xpert-hcv-first-point-care-hepatitis-c-rna-test