COVID-19 update: New test better at identifying who is still infectious

Becton Dickenson and Co’s BD Veritor System for rapid detection of the novel coronavirus is better than gold standard RT-PCR lab tests at distinguishing between infectious and non-infectious virus in swab samples obtained within a week of symptom onset, according to a new study.

One drawback of the RT-PCR (real-time polymerase chain reaction) is that patients can test positive even after they are no longer infectious, because the tests detect small amounts of viral RNA that most likely represent infected cells that have died.

Newer “antigen-based” tests look for viral proteins instead of RNA.

The antigen-based approach could potentially “be used to identify and isolate contagious individuals more effectively than current RNA-based (RT-PCR) testing,” coauthor Celine Roger-Dalbert of BD Life Sciences told Reuters.

“Although it may not replace RNA-based testing, because we still need to identify anyone who was infected in order to trace the spread of the virus, it should help make isolation more efficient and effective as a public health intervention used to slow down the spread of COVID-19,” she added. The study results were published on Monday on medRxiv ahead of peer review.