FDA Issues Approval for New Kind of COVID-19 Test

By Jane Farrell

The Food and Drug Administration (FDA) has issued the first emergency use authorization (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 on May 15, 2020 to Quidel Corporation for the Sofia 2 SARS Antigen FIA.

According to FDA Commissioner Stephen M. Hahn, M.D., and Jeff Shuren, M.D., director of FDA’s Center for Devices and Radiological Health, diagnostic testing is one of the pillars of the U.S. response to COVID-19.

Hahn and Shuren emphasized that the FDA continues to take actions to help make these critical products available, including by issuing EUAs.

During this pandemic, there have been two types of tests for which the FDA has issued EUAs. One type are polymerase chain reaction (PCR) tests, a molecular diagnostic testing technique that detects the genetic material from the virus and can help diagnose an active COVID-19 infection. The other type are serological tests that look for antibodies to the virus, which can help identify individuals who have developed an adaptive immune response to the virus, as part of either an active infection or a prior infection.

Fast-track approval of tests may mean that millions of Americans could be tested each day.

This latest FDA authorization is for an antigen test, which is a new type of diagnostic test designed for rapid detection of the virus that causes COVID-19.

Each category of diagnostic test has its own unique role in the fight against this virus. PCR tests can be incredibly accurate, but running the tests and analyzing the results can take time. One of the main advantages of an antigen test is the speed of the test, which can provide results in minutes. However, Hahn and Shuren said in their statement, antigen tests may not detect all active infections. Antigen tests are very specific for the virus but 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,  and 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.

Additionally, antigen tests are important in the overall response against COVID-19 as they can generally be produced at a lower cost than PCR tests, Hahn and Shuren said in their statement. Once multiple manufacturers enter the market, millions of Americans could be tested each day.

Hahn and Shuren said that this is just the first antigen test to be authorized, and more tests and authorizations are expected to follow.