Several widely used rapid antigen at-home COVID-19 tests are effective at detecting omicron, according to preliminary research published Feb. 28 in MedRxiv.
The research involved 5,506 participants not displaying COVID-19 symptoms who received both polymerase chain reaction home-collection test kits — the gold standard for COVID-19 testing — and one of three rapid test kits: Abbot BinaxNow, Becton Dickinson Veritor At-Home, or Quidel QuickVue. Participants were enrolled from Oct. 18 to Jan. 24, spanning delta and omicron infection waves.
Findings showed the rapid tests performed similarly for both omicron and delta. The research team focused their analysis on 153 people who were PCR-positive. Of those, 61 percent with omicron infections tested positive via a rapid antigen test within 48 hours, compared to 46 percent of those infected with delta — a difference that was not statistically significant,
Overall, rapid tests were better at detecting omicron and delta among people with the highest viral loads, about half of the 153 PCR-positive participants. Among this group, the rapid tests detected more than 90 percent of infections.
"This study adds to the body of evidence that says that omicron can be detected with the home tests that we have," Nathaniel Hafer, PhD, one of the study authors and a molecular biologist at UMass Chan Medical School in Worcester, Mass., told The New York Times.
Earlier reports had found at-home antigen tests had a lower sensitivity during the early stages of infection. "But most of these reports are based on a study comparing antigen tests using nasal swabs with PCR tests using saliva samples; but saliva tests are not used commonly," said Apurv Soni, MD, PhD, principal investigator and assistant professor of medicine at UMass.
"That's where our study is different, because we're comparing the same sampling technique, nasal swabs for both PCR and at-home tests, which is widely used across the country."
Still, larger real-world studies are needed to further validate the efficacy of rapid antigen tests, particularly in the earlier stages of illness. People displaying symptoms or who have been exposed are encouraged to take multiple antigen tests over the course of several days, known as serial testing, to confirm their results.
The study was supported by the ongoing National Institutes of Health Rapid Acceleration of Diagnostics initiative.