Science & Technology

COVID-19: Can antigen test be a game-changer?

Unlike commonly available COVID-19 tests that use polymerase chain reaction, antigen diagnostics work by quickly detecting fragments of virus in a sample  

 
Last Updated: Tuesday 12 May 2020

The United States’ Food and Drug Administration (FDA) has authorised emergency use of the first antigen test that can quickly detect, in a matter of few minutes, if a person has been infected with the novel coronavirus SARS-CoV-2.

Antigen test is a second category of rapid test after the antibody / serological test. It quickly detects fragments of proteins found on the virus through testing swabs collected from nasal and throat cavities.

The emergency use authorisation was issued on May 9, 2020 to Quidel Corporation for antigen test kit called Sofia 2 SARS Antigen FIA. This test is different from existing RT-PCR test and antibody rapid test.

Unlike commonly available COVID-19 tests that use polymerase chain reaction (PCR), antigen diagnostics work by quickly detecting fragments of virus in a sample.

A PCR test is a molecular diagnostic testing technique that detects the genetic material from the virus and helps diagnose an active COVID-19 infection.

The other test is a serological test, which looks for antibodies in the blood. It focussed on proteins made by the immune system, which keeps it healthy by destroying foreign invaders.

Each category of diagnostic test has its own unique role in fighting against COVID-19. While PCR test is the most accurate, running and analysing it takes time. One of the major advantages of antigen test is quick results.

However, an antigen test may not detect all active infections.

According to the FDA, positive results from antigen test are highly accurate. But there is also a higher chance of false negatives. Therefore, it is imperative that negative results from an antigen test are confirmed with an RT-PCR test subsequently.  

Antigen tests are important in response to COVID-19 as it is quick and cost- effective. It can be useful to screen people and identify those who need more definitive test.

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