With the increasing global burden of HCV, the World Health Organization (WHO) notes that improved testing and diagnosis are needed to facilitate access to treatment. This is an especially pressing need for marginalized populations such as homeless individuals and those with a history of injecting drugs. Many of the commonly used rapid diagnostic HCV tests only detect previous exposure via HCV antibodies rather than active infection as indicated by the presence of HCV RNA.
“Given that 25% of individuals spontaneously clear HCV infection, efforts to enhance diagnosis of chronic HCV infection and improve the HCV care cascade requires enhanced uptake of HCV RNA testing,” wrote the authors of the present research. They investigated the sensitivity and specificity of the Xpert® HCV Viral Load (Cepheid) point-of-care assay for detecting HCV RNA in plasma samples collected via venipuncture, as well as in fingerstick capillary whole-blood samples. The Abbott RealTime HCV Viral Load RNA assay was used for comparison.
The final analysis included 150 adults (median age: 44 years; 87% men) participating in drug recovery and homelessness programs across 5 sites. The findings show that HCV RNA was detected in 30% of participants (95% CI: 23%-38%). For plasma collected by venipuncture, sensitivity and specificity of the point-of-care test were 100% (95% CI: 92%-100%) and 99.1% (95% CI: 94.9%-100%), respectively. For the fingerstick samples, sensitivity and specificity were 95.5% (95% CI: 84.5%-99.4%) and 98.1% (95% CI: 93.4%-99.8%), respectively. No adverse events were reported.
The manufacturer of the Xpert HCV Viral Load point-of-care assay is now aiming to optimize the test to produce results within 60 minutes vs 108 minutes, as in this investigation. The reduced time to result is likely to lead to a commercially available fingerstick test to detect HCV RNA.
“The major advance of this point-of-care assay over previous antibody tests, which only indicate HCV exposure, is the ability to detect active HCV infection,” the authors stated. These results also indicate the need for additional “evaluation of the Xpert HCV Viral Load test for HCV RNA detection by finger-stick whole-blood collection as a strategy” to simplify sample collection and increase timely access to treatment. Such testing could vastly improve HCV testing and diagnosis, which is currently inadequate in many parts of the world.