Study Shows Low Incident of False Positive Test Results from Rapid Antigen Tests for COVID-19

A new study investigating the incidence of false-positive results in a large sample of rapid antigen tests used to serially screen asymptomatic workers throughout Canada has shown the overall rate of false-positive results among the total rapid antigen test screens for SARS-CoV-2 to be very low.

The study by researchers at the University of Toronto (Toronto, Canada) looked at the results from rapid antigen tests that were administrated as an extra layer of protection to control transmission in workplaces throughout Canada. The study examined rapid antigen tests conducted by employees from January 11 to October 13, 2021, with some workplaces providing at-home screening and others on-site screening programs. Over this period, Canada experienced two significant variant-driven waves from March to June and August to October. The study found only .05% of over 900,000 tests administered had false-positive results.

The study also revealed that a cluster of false-positives at two workplaces was likely the result of manufacturing issues rather than implementation, and demonstrated the importance of having a comprehensive data system to quickly identify potential issues. With the ability to identify batch issues within 24 hours, workers could return to work, problematic test batches could be discarded, and the public health authorities and manufacturer could be informed.

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