Salivary detection of COVID-19: clinical performance of oral sponge sampling for SARS-CoV-2 testing

New article in ERJ Open Research

From : Jacques Boutros, Jonathan Benzaquen, Charles Hugo Marquette, Marius Ilié, Mickelina Labaky, Didier Benchetrit, Thibaut Lavrut, Sylvie Leroy, Richard Chemla, Michel Carles, Virginie Tanga, Charlotte Maniel, Olivier Bordone, Maryline Allégra, Virginie Lespinet, Julien Fayada, Jennifer Griffonnet, Véronique Hofman, and Paul Hofman


Background The current diagnostic standard for coronavirus disease 2019 (COVID-19) is reverse
transcriptase-polymerase chain reaction (RT-PCR) testing with nasopharyngeal (NP) swabs. The
invasiveness and need for trained personnel make the NP technique unsuited for repeated community-based
mass screening. We developed a technique to collect saliva in a simple and easy way with the sponges that
are usually used for tamponade of epistaxis. This study was carried out to validate the clinical performance
of oral sponge (OS) sampling for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing.

Methods Over a period of 22 weeks, we collected prospectively 409 paired NP and OS samples from
consecutive subjects presenting to a public community-based free screening centre. Subjects were referred
by their attending physician because of recent COVID-19 symptoms (n = 147) or by the contact tracing
staff of the French public health insurance because they were considered as close contacts of a laboratoryconfirmed
COVID-19 case (n = 262).

Results In symptomatic subjects, RT-PCR SARS-CoV-2 testing with OS showed a 96.5% (95% CI: 89.6–
94.8) concordance with NP testing, and a 93.2% (95% CI: 89.1–97.3) sensitivity when using the IdyllaTM
platform and a sensitivity of 76.3% (95% CI: 69.4–83.2) on the Synlab Barla laboratory platform. In close
contacts the NP-OS concordance (93.8%, 95% CI: 90.9–96.7) and OS sensitivity (71.9%, 95% CI: 66.5–77.3)
were slightly lower.

Conclusion These results strongly suggest that OS testing is a straightforward, low-cost and highthroughput
sampling method that can be used for frequent RT-PCR testing of COVID-19 patients and
mass screening of populations.

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