A rapid-results antigen test trumps the more accurate lab-based test in mitigating the spread of COVID-19 in assisted living communities and other long-term care settings, Admiral Brett Giroir, assistant secretary for health at the U.S. Department of Health and Human Services said Monday in a coronavirus policy update for LeadingAge members. Giroir is the federal lead for COVID-19 diagnostic testing efforts.
Although a lab-based PCR test is the “gold standard,” at more than $125 per test, it is an expensive endeavor that the federal government calculated could cost nursing homes an extra $1 billion per month based on outbreak status, Giroir said. If turnaround time on a PCR test is more than 48 hours, the sensitivity of a test is much less important, he added.
Giroir said that the BinaxNOW Ag Card antigen test from Abbott Laboratories, which has a 15-minute turnaround time, “beats sensitivity at every turn.” The antigen test, which is the type of test the federal government is sending to assisted living communities, is simple and less expensive, he said, but it is adequate to pick up a COVID-19-positive person with a “high viral load.”
The antigen tests have been a mainstay of diagnostic testing for flu, strep throat, respiratory syncytial virus and other viruses, Giroir said, and it is acceptable for surveillance testing in congregate care settings even if used off-label. The U.S. Food and Drug Administration and Centers for Medicare & Medicaid Services waived enforcement discretion to use the antigen tests off-label, and Giroir provided provisions for facilities to use the tests under the Public Readiness and Emergency Preparedness, or PREP, ACT.
“These are lifesaving measures,” he said.
Giroir reiterated the federal government’s strategy on distribution on the BinaxNOW antigen tests, stating that the federal government signed a contract for 150 million BinaxNOW cards, 50 million of which will be sent over the next few months to cover vulnerable populations, including assisted living communities, and 100 million of which will be sent to governors and state health officials, who will decide how to use those tests.
Giroir indicated that over the past two weeks, just under 1.5 million tests were sent to assisted living communities with Clinical Laboratory Improvement Amendment, of CLIA, certificates of waiver, and 25 million were sent to home health and hospice organizations.
Assisted living communities and nursing homes located in “red” counties (defined as having positivity rates of more than 10%) that have not received a shipment of BinaxNow tests were advised to email [email protected].
In addressing rates of false-positives from the antigen tests, Giroir said that HHS is working with states on reporting requirements if a test comes back positive in a community where a low prevalence of disease exists. Currently, states can require facilities to report positive test results from the rapid-results antigen tests.
“Particularly among asymptomatic people that you are screening, if you are in a relatively low-prevalence area, no matter what test you use, the chances are, you’re going to get as many false positives as true positives. And in fact if you are in a very, very low-prevalence area, you’re going to get more false positives than true positives,” Giroir said. “That’s not a function of the test; it’s a function of the way life is.”
He encouraged providers to be cautious and to follow up a positive test from an employee with a molecular test.