Using rapid (point-of-care) tests for COVID-19: A decision analysis comparing the expected benefit of two screening strategies

Abstract

Background : Rapid tests for COVID-19 could be used to augment the otherwise limited laboratory-based testing capacity, but there are concerns that their utility may be compromised by their limited accuracy. The objective of this article is to compare the expected benefit (EB) of two screening strategies, one with rapid tests (SwRT) and another one without rapid tests (Sw ̅RT). Methods : We performed a decision analysis, with the overall EB defined as the proportion of correctly identified individuals minus the proportion of incorrectly identified individuals. Accordingly, the SwRT strategy will be deemed a better screening strategy if its lesser EB for COVID-19 free individuals is more than compensated by its greater EB for COVID-19 individuals. Otherwise, it will not. Results : As expected, the EB for COVID-19 individuals was greater for the SwRT strategy, with a far superior ability to rule out the presence of COVID-19. In fact, under the scenario of interest (i.e., 8000 ID Now rapid tests in addition to 28185 lab-based RT-PCR tests), it identified almost 16% more COVID-19 individuals than the Sw ̅RT strategy. In addition, the EB for COVID-19 free individuals was the same for both strategies, with a perfect ability at ruling in the presence of COVID-19. Conclusion : The SwRT strategy identified more COVID-19 individuals and this gain was not obtained at the detriment of COVID-19 free individuals who were equally well identified by both strategies. Hence, the SwRT strategy is a better screening strategy for COVID-19. It represents an opportunity to curtail the spread of SARS-CoV-2 that we may not afford to miss with new more contagious variants becoming more and more common in Canada.