POC Test Advances Hepatitis C Diagnosis
By Labmedica International staff writers
Posted on 10 May 2017
Image: The Xpert HCV Viral Load cartridge, a quantitative test that provides on-demand molecular testing for confirmation of infection and monitoring of Hepatitis C virus (HCV) (Photo courtesy of Cepheid).
A new test that enables diagnosis of hepatitis C infection in a single visit could improve access to early diagnosis, monitoring, and treatment service for some of the most vulnerable people in Australia and the world.
Point-of-care hepatitis C virus (HCV) RNA testing offers an advantage over antibody testing, which only indicates previous exposure, enabling diagnosis of active infection in a single visit. The performance of a HCV Viral Load assay with venipuncture and finger-stick capillary whole-blood samples has been evaluated.
Scientists at the Kirby Institute collected plasma and finger-stick capillary whole-blood samples from participants in an observational cohort enrolled at five sites in Australia, three drug and alcohol clinics, one homelessness service, and one needle and syringe program. Of 210 participants enrolled between February 8, 2016, and July 27, 2016, 150 participants had viral load testing results for the three assays tested.
The scientists compared the sensitivity and specificity of the Xpert HCV Viral Load test for HCV RNA detection by venipuncture and finger-stick collection with their gold standard, the Abbott RealTime HCV Viral Load assay. The Xpert HCV Viral Load test is a quantitative test for rapid measurement of Hepatitis C virus Viral Load and confirmation of HCV infection delivers on-demand results in less than two hours.
HCV RNA was detected in 45 (30%) of 150 participants based on the Abbott RealTime assay. Sensitivity of the Xpert HCV Viral Load assay for HCV RNA detection in plasma collected by venipuncture was 100% and specificity was 99.1%. Sensitivity of the Xpert HCV Viral Load assay for HCV RNA detection in samples collected by finger-stick was 95.5% and specificity was 98.1%. No adverse events caused by the index test or the reference standard was observed. The authors concluded that the Xpert HCV Viral Load test can detect active infection from a finger-stick sample, which represents an advance over antibody-based tests that only indicate past or previous exposure.
Jason Grebely, PhD, an Associate Professor and lead author of the study, said, “Requiring people to come back for a second appointment to receive their results can present significant barriers, especially for people living in remote areas and for vulnerable and marginalized populations like homeless people and people who inject drugs, who are the people we need to reach the most in order to eliminate hepatitis C.” The study was published on April 21, 2017, in the journal The Lancet Gastroenterology & Hepatology.