ABSTRACT
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 22â 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 laboratory-confirmed 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 high-throughput sampling method that can be used for frequent RT-PCR testing of COVID-19 patients and mass screening of populations.
ABSTRACT
BACKGROUND: Management of large numbers of reverse transcriptase-polymerase chain reactions (RT-PCR) for diagnosis of coronavirus 2019 disease (COVID-19) requires robust infrastructures, located in dedicated premises with a high standard of biosafety procedures, and well-trained personnel. The handling of a "run-of-river sample" to obtain rapid reporting of results is challenging. METHODS: We studied the clinical performance of the Idylla™ SARS-CoV-2 Test (index test) on a platform capable of fully automated nucleic acid testing including extraction, amplification, and detection in a single-use cartridge to establish the diagnosis of COVID-19. The study was conducted on a prospective cohort of 112 volunteers with recent symptoms and an unknown SARS-CoV-2 status who came to free screening centers of the Nice metropolitan area. All subjects underwent bilateral nasopharyngeal sampling. One sample was processed using the index test, the other using the standard of care RT-PCR. Samples were treated blind. RESULTS: Most of the participants (70%) were sampled within 4 days of symptom onset. Forty-five (40.2%) were positive for COVID-19. No clinical symptoms were distinguished between SARS-CoV-2 RT-PCR positive and negative subjects except anosmia and dysgeusia. Positive and negative agreement between the index and the standard of care test was 100%. CONCLUSIONS: The Idylla™ SARS-CoV-2 Test is very sensitive, specific, rapid and easy to use in a near-patient RT-PCR approach to distinguish between symptomatic SARS-CoV-2 positive and negative patients in selected settings.