US FDA GIVES EMERGENCY USE APPROVAL TO ANTIGEN TESTS

NEWDELHI:THE US Food and Drug Administration (FDA) on Friday issued an emergency use authorisation (EUA) for Covid-19 antigen tests. It is a new type of test that is easy to carry out and can help with early detection of the virus, right at the doctor’s clinic itself.

This test can quickly detect fragments of proteins found on or within the Sars-cov-2 virus by testing samples collected from the nasal cavity using swabs. The FDA has issued the EUA to Quidel Corporation for what is called Sofia 2 SARS Antigen FIA. The test has been approved for laboratory use as well as for point-ofcare testing at some facilities.

Antigen tests are very specific, but are not as sensitive as molecular PCR tests. This means positive results from antigen tests are highly accurate, but there is a higher chance of false negatives as well - so negative results don’t rule out the infection, the FDA said in a statement on Saturday. Negative results from an antigen test may need to be confirmed with an RT PCR test prior to making treatment decisions.

“Its good to know that now there is an antigen test for Covid-19, but it remains to be seen how accurate it is. Antigen tests are rapid tests which turn positive earlier, which means they can detect an active infection... The greatest benefit of an antigen test is early diagnosis with rapid testing. But the kit has to be of high quality for the antigen test to be accurate,” said Dr Anurag Agrawal, director of CSIR Institute of Genomics and Integrative Biology.

Dr Shobha Broor, former head of the department of virology at the All India Institute of Medical Sciences, said, “The antigen test can detect antigen of the virus. The Sars-cov-2 has spikes, which are antigens that stimulate immune response in the body. These tests turn positive earlier but sensitivity is less compared to RT PCR. But these tests can be done anywhere even in a doctor’s office.”