Evaluating the performance of the Sofia SARS Antigen FIA

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.

Inclusion Criteria:

• Adult patient (> or = 18 years of age)
• Patient with symptoms of COVID-19 (Rhinitis, throat pain, nasal congestion or other signs of local manifestation of the disease in the upper respiratory tract, including loss of taste, with or without additional systemic symptoms such as fatigue, fever, muscle pain...) whose health condition does not require hospitalization (mild to moderate disease)
• Patient with these symptoms for 5 days or less with a median of 3 to 4 days.
• Patient with consent to participate in the study

Exclusion Criteria:

• Patient with an age below 18 years
• Patient under legal protection (guardianship, curatorship)
• Patient without upper respiratory tract symptoms
• Patients with symptoms for more than 5 days
• Patient with previous COVID-19 diagnosed by RT-PCR
• Patient vaccinated against SARS-CoV-2 (1 or 2 injections)
• Hospitalized patient
• Refusal to participate

Two nasopharyngeal swabs will be taken per included patient. One will be analyzed by RT-PCR in the virology laboratory, the other will be analyzed on site with the Sofia SARS Antigen FIA test. The results of the two tests will then be compared.

These samples will not be collected for further research.

All collected data that underlie results in a publication

Data will be available beginning three month and ending five years following the publication

Data access requests will be reviewed by the internal committee of Brest UH. Requestors will be required to sign and complete a data access agreement.