On Mar. 8, 2023, QuidelOrtho announced that it had been granted a De Novo request from the U.S. Food and Drug Administration, allowing the company to market its Sofia 2 SARS Antigen+ FIA. The Sofia 2 SARS Antigen+ FIA is the first rapid antigen test that detects COVID-19 to be awarded FDA market clearance. The test is intended for prescription use only and can be used in point-of-care settings.

The Sofia 2 SARS Antigen+ FIA is a lateral flow immunofluorescent assay that is used with the Sofia 2 fluorescent immunoassay analyzer intended for the qualitative detection of the nucleocapsid protein antigen of SARS-CoV-2 in direct anterior nasal swab specimens from individuals with signs and symptoms of upper respiratory infection (i.e., symptomatic) when testing is started within six days of symptom onset. The test is intended for use as an aid in the diagnosis of SARS-CoV-2 infections (COVID-19) in symptomatic individuals when tested at least twice over three days with at least 48 hours between tests. The Sofia 2 SARS Antigen+ FIA is intended for use by trained clinical laboratory personnel and individuals trained in point-of-care settings and proficient in performing tests using Sofia 2 instruments.

The enhanced Sofia 2 SARS Antigen+ FIA Test kit includes other upgraded features, such as prefilled reagent vials, improved ergonomic sample extraction and a dropper design for easy dispensing of patient samples into the test cassette sample well. The Sofia 2 instrument also offers two distinct workflows. Depending upon the user’s preferred operational method, Sofia 2 SARS Antigen+ FIA test cartridges are either placed directly inside Sofia 2 for automatically timed test development and results read (WALK AWAY Mode), or test cartridges may be placed on the counter or benchtop for a manually timed test development and then placed into Sofia 2 for immediate results read (READ NOW Mode), which allows users to markedly increase testing throughputs per hour.

Results are for the identification of the SARS-CoV-2 nucleocapsid protein antigen, which is generally detectable in upper respiratory specimens during the acute phase of infection. Positive results indicate the presence of viral antigens of SARS-CoV-2, but clinical correlation with patient history and other diagnostic information is necessary to determine infection status. Positive results do not rule out bacterial infection or co-infection with other viruses, as the agent detected may not be the definite cause of disease.

A negative test is presumptive, and it is recommended these results be confirmed by a molecular SARS-CoV-2 assay. Negative results do not preclude SARS-CoV-2 infection and should not be used as the sole basis for treatment or patient management decisions.