About a quarter of nursing homes have seen at least one false positive COVID-19 result during an ongoing federal push to provide point-of-care antigen testing at most facilities across the country, according to an industry-led survey.
“We found that about 20-25 percent of SNFs had a positive antigen test result later found to be incorrect using PCR testing,” the American Health Care Association and LeadingAge reported last week in a blog post on the former’s website. “The vast majority had only 1-3 ‘potential false positives’; 26 (or 3 percent) had more than 5 potential false positives.”
The trade groups, which together represent the vast majority of nursing facilities nationwide, polled about 1,100 respondents about their experiences with point-of-care units from manufacturers Becton Dickinson and Quidel.
The organizations emphasized that the false-positive rate isn’t necessarily surprising.
“While any potential false positive results are concerning, this appears to be consistent with what you would expect to see with widespread testing of many people in communities with relative low rates of COVID-19,” the groups wrote in the blog post.
BD and Quidel are investigating the reports of false positives, according to AHCA and LeadingAge; the manufacturers’ preliminary inquiries “have not revealed any abnormalities” so far.
The trade groups encouraged operators to contact BD and Quidel with any concerns over false positives, while also ensuring that staff are properly trained on the machines’ use.
A Centers for Medicare & Medicaid Services (CMS) official on Monday confirmed that the agency is looking into the reports of false negatives, but also allowed that it’s too soon to make wholesale changes to testing policy. The problem, according to the official, could potentially be related to a number of factors — from the units themselves to testing kits to the collection procedures to the profile of the people who are receiving the tests.
“The bottom line is that we are really in information-gathering mode, to better understand the context and the scope of where test results are false positives,” the official said on a call with industry stakeholders.
Since July, the Department of Health and Human Services (HHS) has been sending the antigen testing units, along with a single round of necessary supplies, to most nursing homes in an attempt to facilitate frequent, routine screening of residents and staff.
The antigen method is less sensitive than the “gold standard” polymerase chain reaction (PCR) tests, which generally must be performed at third-party laboratories. But the federal government has asserted that routine PCR testing is simply too costly and time-consuming to serve as the backbone of a nationwide nursing home testing strategy.
“If you can meet CMS standards with highly sensitive molecular tests using PCR, testing residents and staff as often as twice per week, with a turnaround time of 24 hours or less, and can afford to do that — that’s about $1 billion per month in the industry — it is perfectly appropriate to use molecular PCR tests,” he said. “If you cannot, as most nursing homes cannot, point-of-care antigen testing is clearly a life-saving option and is available in quantities of 10 billion per month or more.”
The Wall Street Journal last week reported that BD was looking into reports of false positives at “roughly a dozen” facilities. In one instance, a facility moved several asymptomatic patients into a COVID-only wing based on the results, according to the publication, only for follow-up PCR tests to reveal that they were all actually negative.
CMS understands that nursing homes are using the tests to make “population management decisions,” according to the official.
The potential for confusion prompted AHCA and LeadingAge to call on HHS for more clarity around the proper protocols for handling false positives. In addition to resident and staff safety, the testing initiative plays a role in a variety of reporting requirements for operators, as well as a new HHS push to base $2 billion in relief funding on facilities’ performance with reducing infections and deaths.
“We understand that members are receiving different directives from their state health departments ranging from being required to report all positive test results, even if they are found to conflict with confirmation testing, to being advised not to use the antigen analyzers,” they observed. “We are working aggressively with HHS to get written information out to address what to do in the case of potential false positives, whether from antigen or PCR tests.”