Performance of the OraQuick Hepatitis C virus antibody test in oral fluid and fingerstick blood before and after treatment-induced viral clearance

Abstract

BackgroundA reliable population screening strategy for hepatitis C virus (HCV) infection may be based in easy-to-use point-of-care (POC) tests for HCV antibodies, but validation data is needed before their potential widespread use in primary care or outreach practice. Besides, the sensitivity of these POC tests in patients with spontaneous or treatment-induced viral clearance is unknown. ObjectivesTo test the performance of a non-invasive POC anti-HCV test (OraQuick HCV rapid test) in oral mucosal transudate (OMT) and fingerstick blood from patients with known anti-HCV serostatus and with or without active viremia (after treatment-induced clearance). Study designA risk factor questionnaire was collected from 317 consecutive patients (anti-HCV positive/HCV-RNA positive n = 107; anti-HCV positive/HCV-RNA negative after antiviral treatment n = 107; anti-HCV negative with other liver diseases n = 109) before performing the OraQuick HCV rapid test in OMT (n = 317) and fingerstick blood (n = 251). We calculated the sensitivity and specificity of the test by using anti-HCV serostatus as the reference gold-standard. ResultsAmong all anti-HCV seropositive patients, the clinical sensitivity and specificity of the OraQuick HCV rapid test in OMT was 89.9% and 100%, respectively. In fingerstick blood, the sensitivity improved to 98.8%. The sensitivity was higher in OMT (97.2%) in anti-HCV seropositive patients who were viremic as compared to that in non-viremic individuals (82.2%). In contrast, there were no significant differences in sensitivity between viremic and non-viremic individuals when testing fingerstick blood. Finally, extension of the read time to 40 min enhanced the sensitivity, especially in OMT (up to 94.7%) and in the subgroup of non-viremic, anti-HCV-positive patients (up to 90.1%). ConclusionsThe OraQuick HCV rapid test in OMT has a high sensitivity and specificity for detecting active HCV infection that decreases substantially in anti-HCV positive/HCV-RNA negative patients with treatment-induced viral clearance. For these individuals, extension of read times and testing fingerstick blood showed improved sensitivity.