The FDA issued the first EUA for a new category of tests to be used in the ongoing COVID-19 pandemic.
Antigen tests are a new category of COVID-19 tests that work by quickly detecting fragments of proteins found on or within the virus by testing samples collected from the nasal cavity using swabs.
The EUA was issued to Quidel Corporation for the Sofia 2 SARS Antigen FIA for use in high and moderate complexity laboratories certified by Clinical Laboratory Improvement Amendments (CLIA) as well as for point-of-care testing by facilities operating under a CLIA Certificate of Waiver.
“Diagnostic testing is one of the pillars of our nation’s response to COVID-19 and the FDA continues to take actions to help make these critical products available, including by issuing EUAs,” said the FDA statement released May 9, 2020.
Unlike polymerase chain reaction (PCR) tests that are used to diagnose an active COVID-19 infection and can take up to 6 hours from start to finish to complete, antigen tests can provide results in minutes.
While they deliver results faster than PCR, however, antigen tests may not detect all active infections as they are very specific for the COVID-19 virus but are not as sensitive as molecular PCR tests. Positive results from antigen tests are highly accurate, but there is a higher chance of false negatives.
With this in mind, health care providers administrating antigen tests may need to confirm negative test results with a PCR test before making any treatment decisions or to prevent possible transmission of COVID-19 due to a false negative.
Antigen tests are also important in the ongoing COVID-19 response as they can generally be produced at a lower cost vs PCR tests and—once multiple manufacturers enter the market—can potentially test millions of Americans every day due to their simple design.
“Antigen tests will play a critical role in the fight against COVID-19 and we will continue to offer support and expertise to help with the development of accurate tests, and to review and monitor marketed tests to ensure accuracy, while balancing the urgent need for these critical diagnostics,” the FDA concluded in its statement.