Johns Hopkins study: Results from rapid COVID tests done at home can be trusted
BALTIMORE — People can test themselves about as accurately at home with rapid antigen coronavirus tests as health care professional using the same tests, according to a Johns Hopkins Medicine-led study published online this week.
In the study, which involved nearly 1,000 patients seen at the Baltimore Convention Center Field Hospital during a five-month period in 2022, researchers found that self-administered COVID tests rivaled those administered by clinicians in their ability to determine accurate positive and negative results.
Self-administered tests were 83.9% accurate in determining positive results — compared to 88.2% for clinician-administered tests — and 99.8% accurate in determining negative results, compared to 99.6%.
“We believe this is an important finding because it suggests physicians can feel confident prescribing treatment based on patient-reported, self-administered tests with positive results,” study senior author Dr. Zishan Siddiqui said in a Johns Hopkins news release on Tuesday. Siddiqui is an assistant professor of medicine at the Johns Hopkins University School of Medicine.
The study was posted online Tuesday in the American Society for Microbiology journal Microbiology Spectrum.
While polymerase chase reaction, or PCR, COVID tests are more accurate than rapid antigen tests, they must be administered by a skilled laboratory technician, require special equipment and take up to an hour or more to process. Testing on a massive scale can only be done at a large, centralized testing facility, whereas rapid tests can be administered at home by anyone and provide results in about 15 minutes.
For the study, Johns Hopkins researchers worked with researchers at the University of Maryland School of Medicine and five other organizations. Together, they enrolled 953 participants between Feb. 12 and July 15, 2022, at the State Center complex in Midtown Baltimore.
The temporary testing site closed last year after opening in April 2020 to treat COVID patients during the pandemic and help relieve an expected surge that could overwhelm area hospitals. It also offered free COVID tests and, eventually, vaccines.
Researchers conducted both a rapid and PCR test on study participants, and had them give themselves a rapid test and report their own results. The participant pool was 60.6% female, 58.6% white and 98.2% English-speaking, and the median age was 34, according to the Hopkins news release.
In an earlier Hopkins-led study at the Baltimore Convention Center Field Hospital, researchers demonstrated that rapid COVID tests had comparable accuracy to PCR tests.
“The first study suggested that a health care system can provide an equitable response to COVID-19, with (rapid antigen tests) making it possible to test all socioeconomic levels of a large population quickly and repeatedly,” Siddiqui said in the release. “The new study bolsters that belief by showing comparable accuracy between self- and physician-performed (rapid antigen tests) and, therefore, helping build clinician confidence in patient-reported results from at-home tests.”
The rapid antigen test used in the study was the BinaxNOW COVID test manufactured by Abbott and supplied at no cost by the Maryland Department of Health.
Future studies “should look at an array of brands across a broader demographic spectrum so that our results can hopefully be confirmed and amplified,” said Mary Jane Vaeth, the study’s lead author, in the Hopkins news release. Vaeth was a clinical assistant at the now-closed field hospital.
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