Evaluation of the Sofia SARS Antigen FIA Assay for COVID-19

RT-PCR is the reference technique for the diagnosis of COVID-19, as recommended by WHO, ECDC and the HAS College. Serological tests to identify antibodies developed by the immune system following infection with SARS-CoV-2 are not currently recommended as a first-line test for the initial diagnosis of COVID-19. However, they can be used in cases of negative RT-PCR and suggestive clinical presentation, or as a salvage test when RT-PCR could not be performed within 7 days of symptom onset. Antigenic tests for the detection of SARS-CoV-2 can be used as a first-line test on nasopharyngeal swabs up to and including 4 days after the onset of symptoms. From the 5th day, only detection by gene amplification is indicated. Given their excellent specificity and the current pandemic situation, it is not necessary to confirm positives with a gene amplification test. However, it is recommended to perform a gene amplification test when the antigenic test result is negative or uninterpretable in symptomatic patients older than 65 years or with at least one risk factor for severe COVID-19. For contact persons detected in isolation or in clusters, it is also possible to use antigenic tests in the following cases * as soon as possible and then at 7 days for high-risk contacts (within the same household as an infected patient) ; * 7 days after exposure for other contacts (low risk). Given the rapidity of antigenic test results (15 to 30 minutes), the good performance of the Sofia SARS Antigen FIA test in target populations and its traceability, it could be used as a first-line test in emergency rooms and screening centers and thus have a positive impact on the management of ambulatory patients and, by corollary, on viral transmission.