At-home direct rapid antigen tests may catch all new COVID-19 cases if used twice a week, new data suggest.

Researchers had 257 employees use the tests twice a week for six months and also undergo regular qRT-PCR tests. The home tests caught all 15 cases, 11 on day one or two, according to the report published in JAMA Network Open.

“We were faced with an issue to solve,” said the study’s senior author, Laura Holberger, vice president of strategic partnerships at BioInnovation Labs, LLC, a privately held network of co-working labs with locations in biotech hub cities across the country.

“Employees of biotech companies can’t work from home,” Holberger said. “We had to come up with a solution to help advance the research of the member companies.”

“The main take home is that with this protocol we were able to detect all 15 infections and prvent all cases of community spread during the pandemic,” Holberger said.

The new study included workers at three co-working laboratories in the Massachusetts cities of Cambridge and Boston. At the time, the prevalence of COVID-19 in this area ranged from less than 1 percent to 8 percent.

Participants self-collected nasal swab specimens twice weekly at home for the Direct Antigen Rapid Test (DART) from E25Bio Inc., and the findings were compared with laboratory qRT-PCR tests.

“The process of administering the antigen test involves swabbing both nostrils, suspending the sample in a small volume of buffer and using a dropper to apply the sample to the test cassette,” Holberger explained. “The sample flows over the test window which reads out the result with a positive control.”

Information on symptoms was collected contemporaneously. Self-reported race and ethnicity were also collected in accordance with Department of Health and Human Services and Food and Drug Administration reporting guidelines for non-laboratory-based tests.

The median participant age was 35, 120 (46.7 percent) were women, 161 (62.6 percent) were white, 49 (19.1 percent) were Asian, 29 (11.3 percent) were Hispanic, and 8 (3.1 percent) were Black. A total of 2,951 pairs of nasal swabs were self-collected by participants and tested by qRT-PCR and DART.

The sensitivity of DART within days 0 to 12 of symptom onset was 78.9 percent (60 of 76 swabs), and the specificity of DART was 97.1 percent (2,791 of 2,875 swabs).

The duration of SARS-CoV-2 nucleocapsid and RNA detection for individual infections ranged from one to 12 days, with peak levels observed between 2 and 6 days of symptoms (median, three days).