Early Read-Time Performance of the OraQuick HCV Rapid Antibody Assay for the Exclusion of HCV Viremia

Abstract

Rapid point-of-care tests for hepatitis C virus (HCV) provide results in 20 min and allow linkage to care, particularly for difficult-to-reach populations. Prior work suggested an early reading time of the OraQuick (OQ) rapid HCV antibody lateral flow immunoassay identified people with HCV viremia; however, these observations were not externally validated. We conducted a prospective cohort study at Penn Presbyterian Medical Center from June 2021 to August 2023 to evaluate the performance of OQ early reading times for HCV viremia among participants with reactive HCV antibody. Following test device insertion for whole blood substrate, the OQ assay was evaluated every minute from 5 to 10 min, then at 20 and 40 min. Early read time performance was evaluated against the standard of care HCV RNA. 175 participants (120 [68.6%] with detectable HCV viremia) completed the OQ assay. Among HCV viremic participants, 119 had a positive whole blood OQ by 7 min (sensitivity: 99.2% [95% confidence interval, CI: 95.4–100]; positive predictive value: 82.1% [95% CI: 74.8–87.9]); 1 viremic participant with severe immunosuppression was not identified at this early reading time. No time interval accurately identified only those with HCV viremia, yet a negative OQ test at 7 min excluded HCV viremia (negative predictive value: 96.3% [95% CI: 81.0–99.9]). A 7-min reading time for a whole blood OQ assay may reduce the need for HCV RNA testing and improve screening efficiency by identifying people without HCV viremia. Early read time results cannot be used to exclusively identify HCV viremia and should be used with caution in those with severe immunosuppression or if acute HCV infection is suspected.