The global SARS-CoV-2 pandemic has continued despite implementation of significant public health measures (1). Over 155 million worldwide cases of COVID-19 and over 3 million COVID-19 deaths have been reported as of May 2021. Rapid identification of SARS-CoV-2 infection, patient isolation, and contact tracing are essential for disease containment (2). The current gold standard for detecting SARS-CoV-2 is reverse transcriptase PCR (RT-PCR) (3). While RT-PCR can detect nucleic acids from SARS-CoV-2 with high sensitivity, RT-PCR requires equipment and special training and can take days for results to be available following sample collection (4). Due to the transmissibility of SARS-CoV-2 (basic reproductive number R0 of 2.87), long turnaround times for results may lead to a high number of avoidable transmissions (5, 6).

In contrast, lateral flow immunoassays (LFAs) are an inexpensive testing solution that can be used at point-of-care settings, do not require laboratory equipment, and can generate results quickly. However, the performance of LFA-based SARS-CoV-2 rapid antigen tests in community testing settings can vary significantly (7–9).


In this study, we evaluated the clinical performance of the LFA-based INDICAID COVID-19 rapid antigen test (INDICAID rapid test) by PHASE Scientific International Ltd. A prospective multisite clinical study was performed in symptomatic patient populations in point-of-care (POC) community testing sites in the United States. The performance of the INDICAID rapid test was also evaluated in COVID-19 outbreak screening centers in Hong Kong as a part of an algorithm testing approach (termed “dual-track”) to screen for COVID-19-positive patients prior to RT-PCR testing in asymptomatic patient populations.

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