Evaluation of the INDICAID COVID-19 Rapid Antigen Test in symptomatic populations and asymptomatic community testing

Chiu, R.; Kojima, N.; Mosley, G.; Cheng, K. K.; Pereira, D.; Brobeck, M.; Chan, T. L.; Zee, J. S.-T.; Kittur, H.; Chung, T.; Tsang, E.; Maran, K.; Yung, R. W.-H.; Leung, A. C.-P.; Siu, R.; Ng, J.; Choi, T. H.; Fung, M. W.; Parkin, S.; Chan, W. S.; Lam, H. Y.; Lee, K. K.; Chao, F. C.; Ho, S. K.-K.; MArshak, D.; Ma, E. S.-K.; Klausner, J. D.

Background As the COVID-19 pandemic continues to cause substantial morbidity and mortality, there is an increased need for rapid, accessible assays for SARS-CoV-2 detection. Methods Here we present a clinical evaluation and real-world implementation of the INDICAID COVID-19 Rapid Antigen Test (INDICAID Rapid Test). A multi-site clinical evaluation of the INDICAID Rapid Test using prospectively collected samples from symptomatic subjects was performed. The INDICAID Rapid Test was then implemented at COVID-19 outbreak screening centers in Hong Kong to screen individuals for COVID-19 to prioritize confirmatory RT-PCR testing among asymptomatic populations. Results The clinical evaluation in symptomatic patient populations demonstrated a positive percent agreement and negative percent agreement of 85.3% (95% confidence interval [95% CI]: 75.6% - 91.6%) and 94.9% (95% CI: 91.6% - 96.9%), respectively, when compared to laboratory-based RT-PCR testing. When used during outbreak testing of 22,994 asymptomatic patients, the INDICAID Rapid Test demonstrated a positive percent agreement of 84.2% (95% CI: 69.6% - 92.6%) and a negative percent agreement of 99.9% (95% CI: 99.9% - 100%) compared to laboratory-based RT-PCR testing. When incorporated in a testing algorithm, the INDICAID Rapid Test reduced time to confirmatory positive result from an average 10.85 hours (standard RT-PCR only) to 0.84 hours, depending on the algorithm. Conclusion The INDICAID Rapid Test has excellent performance when compared to laboratory-based RT-PCR testing, and when used in tandem with RT-PCR, reduces the time to confirmatory positive result.