Objective: Post-marketing surveillance was conducted to monitor the performance of the OraQuick Advance rapid HIV-1/2 antibody test (OraQuick) on whole blood and oral fluid.
Design: Surveillance of routinely collected data on clients tested with OraQuick in 368 testing sites affiliated with 17 state and city health departments between 11 August 2004 and 30 June 2005.
Methods: For whole blood and oral fluid, we report the median (range) health department OraQuick specificity and positive predictive value (PPV), and the number of clients with discordant results (e.g. who had a reactive rapid test not confirmed positive by Western blot or indirect immunofluorescence). At one site with lower than expected oral-fluid specificity, we evaluated whether device expiration, manufacturing lot, operator practices, or device-storage or testing-area temperatures were associated with false-positive tests.
Results: During the surveillance period, 135 724 whole blood and 26 066 oral fluid rapid tests were conducted. The median health department whole blood OraQuick specificity was 99.98% (range: 99.73-100%) and PPV was 99.24% (range: 66.67-100%); the median oral fluid specificity was 99.89% (range: 99.44-100%) and PPV was 90.00% (range: 50.00-100%). A total of 124 discordant results were reported from 68 (0.05%) whole blood and 56 (0.22%) oral fluid rapid tests. The oral fluid specificity at the site with excess oral fluid false-positive tests was 98.7% (95% confidence interval: 98.18-99.11%). The increase in false-positive tests at that site was not associated with any specific device characteristic, operator procedure or temperature condition.
Conclusion: The specificity of OraQuick performed on whole blood and oral fluid during post-marketing surveillance was compatible with the manufacturer's claim within the package insert. However, one site experienced lower than expected oral fluid specificity. Sites that observe that the specificity of OraQuick is lower than the range indicated in the package insert should notify the manufacturer and evaluate quality assurance procedures.