These diagnostic tests quickly detect fragments of proteins found on or within the virus by testing samples collected from the nasal cavity using swabs
The US Food and Drug Administration has issued the first emergency use authorisation (EUA) for a COVID-19 antigen test, a new category of tests for use in the ongoing pandemic. These diagnostic tests quickly detect 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. This test is authorised 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.
This latest FDA authorisation is for an antigen test, which is a new type of diagnostic test designed for rapid detection of the virus that causes COVID-19. One of the main advantages of an antigen test is the speed of the test, which can provide results in minutes. However, they are not as sensitive as molecular PCR tests. This means that positive results from antigen tests are highly accurate, but there is a higher chance of false negatives, so negative results do not rule out infection. With this in mind, negative results from an antigen test may need to be confirmed with a PCR test prior to making treatment decisions or to prevent the possible spread of the virus due to a false negative.
Antigen tests are also important in the overall response against COVID-19 as they can generally be produced at a lower cost than PCR tests and can potentially scale to test millions per day due to their simpler design.