A point-of-care test that can detect active infection with hepatitis C virus (HCV) from a finger-stick sample and provides results in less than two hours showed good sensitivity and specificity in a multicenter Australian study.
The Xpert HCV Viral Load test (Cepheid, Sunnyvale, Calif.) represents an advance over current antibody-based tests, which indicate only past exposure to HCV. The test can detect HCV RNA in capillary whole blood collected by finger-stick and in plasma collected by venipuncture.
The open observational cohort study was conducted at five sites: three drug and alcohol clinics, one homelessness service, and one needle and syringe program.
“The results from this study are encouraging, given that the performance of rapid diagnostic tests in clinical settings is poorer than in the laboratory,” the researchers wrote in a paper online April 21 in The Lancet Gastroenterology and Hepatology.
Given that 25% of people will spontaneously clear their HCV infection, “the availability of a point of care test to detect active HCV infection represents a major advance over previous point of care HCV tests, which only test for exposure to the virus,” corresponding author Dr. Jason Grebely, of The Kirby Institute, University of New South Wales, Sydney, told Reuters Health by email.
“We need to continue to move towards low-cost, rapid tests for detecting active HCV infection, because in many countries the cost of screening large numbers of people will be a big barrier towards large improvements in HCV diagnosis,” he added.
“Sensitive HCV RNA testing of whole blood collected by finger-stick is particularly appropriate for populations with a high prevalence of HCV infection,” such as the individuals in this study, he said. “Often these people are highly marginalized, so having an opportunity to engage people in testing, linkage to care, and treatment in a single visit may reduce drop-outs along the HCV cascade of care.”
Dr. Grebely cautioned, however, that the test is not yet approved in many countries and that further studies are needed to evaluate the assay in different settings and populations, such as patients given direct-acting antiviral therapy, those with a sustained virological response, or those with HIV/HCV co-infection.
In an accompanying commentary, Dr. Curtis Cooper of the University of Ottawa, Ontario, Canada cited some of the substantial obstacles that keep HCV-infected individuals from accessing care, including the shortcomings of current diagnostic tests. He explained that rapid HCV RNA testing can reduce the impact of these barriers.