Nose swabbing best for rapid antigen tests, studies find
10111 Min Read
Users of rapid antigen tests to detect COVID-19 should swab their nostrils as directed by the manufacturer and not swab the throat or cheek instead, new research shows.
Earlier this month, with Omicron accounting for nearly all coronavirus infections in San Francisco, researchers there performed both PCR and Abbott Laboratories’ BinaxNOW rapid antigen test on 731 people requesting COVID-19 tests.
Nasal swabbing “detected over 95% of persons with the highest levels of virus who are most likely contagious,” said Dr. Diane Havlir of the University of California, San Francisco. In 115 volunteers with positive PCR tests, her team compared BinaxNOW results using swab samples from the nose and the throat obtained by trained professionals.
Throat swabs detected nearly 40% fewer cases than nose swabs, they reported on medRxiv ahead of peer review. A separate study from Spain, also posted on medRxiv, found that swabbing the inside of the cheek also is far less reliable than nostril swabbing for detecting infectious virus. Recent studies had suggested that Omicron is detectable earlier in the throat than in the nose, leading some experts to advise users to swab the throat, although the U.S. Food and Drug Administration maintained the tests should be used as directed.
“These data support using BinaxNOW from nasal swabs as directed on the package,” Havlir said.
“Repeat rapid testing is recommended for those with negative BinaxNOW rapid tests and symptoms or an exposure” to an infected person.
