Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Buccal Screening Evaluation Using an RT-PCR Assay and a Rapid ELISA Test Among Symptomatic and Asymptomatic Patients: the CORDAGES Study

The main objective is to expand screening for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by evaluating the diagnostic accuracy of the RT-PCR test (Cobas® Roche, Switzerland) and the ELISA Point of Contact Testing (PORTABLE COVID-19 ANTIGEN LAB® Stark, Italy) on buccal swab compared to the reference test, the RT-PCR test (Cobas® Roche, Switzerland) on nasopharyngeal swab.

Secondary objectives

• To evaluate the diagnostic accuracy of oral swab RT-PCR and POCT relative to the quantitative amplification (Ct) values of the NP Swab RT-PCR assay.
• Analyze RT-PCR amplification cycle thresholds (Ct) and POCT diagnostic accuracy as a function of the presence and timing of symptoms.
• Among symptomatic participants, compare clinical presentations between positive and negative participants on the NP swab RT-PCR test.
• The RT-PCR test may be imperfectly sensitive, ranging from 71 to 98%3. Using a Bayesian latent class model, the investigators will assess the true accuracy of POCT as it does not require the assumption that any one test or combination of tests is perfect14,15.