Comparative sensitivity of different self-sampling methods for SARS-CoV-2 RT-PCR testing

Abstract

<p><strong>Background: </strong>Alternative sampling methods allow for the possibility for self-collection to facilitate SARS-CoV-2 testing in ambulatory care settings. Self-sampling has been well defined for influenza in community settings, but remains unclear in the context of coronavirus disease (COVID-19). A systematic review and meta-analysis assessing the comparative sensitivity of different self-sampling methods for SARS-CoV-2 testing is needed.</p><p><strong>Methods: </strong>In this meta-analysis, we systematically searched 4 different databases and 2 preprint platforms. We included original clinical studies that examined the performance of nasopharyngeal swabs and any additional respiratory specimens for the diagnosis of SARS-CoV-2 infection among individuals presenting in ambulatory care. Studies without data on paired samples, or those that only examined different samples from confirmed SARS-CoV-2 cases were not useful for examining diagnostic performance of a test and were excluded. Sensitivity of the diagnostic test was examined using random effects models.</p><p><strong>Results: </strong>A total of 26 studies including 9684 participants were included. Using nasopharyngeal swabs as the gold standard, pooled nasal and throat swabs gave the highest sensitivity of 97% [95% confidence interval (CI): 93–100%], whereas lower sensitivities were achieved by nasal swabs (86%, 77–93%), saliva (85%, 75–93%) and gargle (85%, 65–98%), and a much lower sensitivity by throat swabs (68%, 35–94%). Comparison between health-care-worker collection and self-collection for pooled nasal and throat swabs and nasal swabs showed comparable sensitivity.</p><p><strong>Conclusions: </strong>Our review suggests that pooled nasal and throat swabs would be the best alternative sampling approach to nasopharyngeal swabs, for diagnosis of SARS-CoV-2 infection in ambulatory care. Saliva, gargle and nasal swabs gave a comparably good and still reasonable sensitivity and are clinically acceptable alternative sampling approaches. All these alternative sampling approaches appeared as a feasible option to facilitate self-collection of specimens and scaling up of diagnostic testing programs. Throat swabs gave a much lower sensitivity and should not be recommended.</p>