Accuracy of COVID-19 rapid antigenic tests compared to RT-PCR in a student population: the StudyCov study

Ferté, Thomas; Ramel, Viviane; Cazanave, Charles; Lafon, Marie-Edith; Bébéar, Cécile; Malvy, Denis; Georges-Walryck, Agnès; Dehail, Patrick

OBJECTIVE: There is a lack of data evaluating performance of antigenic test (AT) for SARS-CoV-2 diagnosis (Ag-RDT) in clinical practice, especially in asymptomatic subjects. The main objective of this study was to evaluate the diagnostic performance of AT compared to Reverse Transcription Polymerase Chain Reaction (RT-PCR) for SARS-CoV-2 diagnosis. METHODS: StudyCov is a monocentric cross-sectional study. A SARS-CoV-2 screening facility was set up in the Bordeaux University health campus from October 28(th) to November 20(th) 2020. Students willing to have a RT-PCR test (ARGENE SARS-CoV-2 R-GENE, BioMérieux, France) for SARS-CoV-2 diagnosis were also offered the Abbott Panbio™ SARS-CoV-2 antigenic rapid test. All participants attending the screening facility with an AT in addition to RT-PCR and having signed an informed consent were included in the study. The main objective was to assess performance of AT as compared with RT-PCR in the recruited population. Secondary objectives dealt with the analysis of the main objective stratified by current symptoms and risk exposure. A sensitivity analysis with different RT-PCR cycle thresholds was included. RESULTS: RT-PCR and AT results were available for 692 subjects. Overall sensitivity and specificity of AT tests were respectively 63.5% (95% confidence interval (CI): 49.0 – 76.4) and 100% (95% CI: 99.4 – 100). In the asymptomatic sub-group, they were respectively 35.0% (95% CI: 15.4% - 59.2%) and 100% (95% CI: 99.3 - 100). CONCLUSIONS: This study shows the poor sensitivity of AT in asymptomatic subjects, specificity being however excellent. The performance results fall below the World Health Organization recommendation of 80% sensitivity and question using AT in general population, especially when asymptomatic.