Under pressure from the federal government, Nevada health officials on Friday rescinded a statewide order directing nursing homes to halt the use of two government-issued rapid coronavirus tests that the state had deemed to be inaccurate.
The reversal came shortly after the United States Department of Health and Human Services issued a threatening letter, dated Oct. 8, to Nevada officials. The federal document noted that swift punitive actions could be taken if the state did not promptly revoke its ban, which Adm. Brett Giroir, assistant secretary of Health and Human Services, called “unwise, uninformed and unlawful” and a violation of the Public Readiness and Emergency Preparedness Act.
Outside health experts who reviewed the letter, which condemned the state’s actions as “based on a lack of knowledge or bias,” described its tone as “acid.”
In a statement released on Friday, Dr. Ihsan Azzam, Nevada’s chief medical officer, said that he and his colleagues were “very disappointed by the letter received today.” Nevada’s priorities, Dr. Azzam said, remained aligned with the federal government’s: to protect “those most vulnerable in our communities from Covid-19.”
About 40 percent of the country’s known Covid-19 deaths have come from nursing homes, according to an analysis by The New York Times.
The two brands of rapid tests, manufactured by Quidel and Becton, Dickinson and Company, had been shipped en masse to nursing homes around the country in August to address the delays and equipment shortages that for months had stymied laboratory testing. Both tests detect bits of coronavirus protein, or antigens.
In submitting applications to the Food and Drug Administration for emergency clearance, BD and Quidel reported no false positives from their products, and advertised these accuracy rates on their packaging.
But among a sample of 39 positive antigen test results collected from nursing homes across Nevada, 23 were found to be false positives when confirmed by a more accurate laboratory test. The discovery prompted state officials to issue their directive on Oct. 2, urging nursing homes to promptly pivot from antigen tests to other types of tests that look for viral RNA while the discrepancies were being investigated.
Dr. Valerie Fitzhugh, a pathologist at Rutgers University, said the number of false positives the state had reported was “significant” and worthy of scrutiny. “In the meantime, switching to an alternative, accurate method of testing would be the responsible thing to do,” Dr. Fitzhugh said. “Nevada was on the right track for trying to fix this issue.”
A week later, however, Admiral Giroir cracked down on Nevada’s “illegal” prohibition on BD’s and Quidel’s tests, which he said had imperiled the residents and staff of nursing homes across the state. “They cannot supersede the PREP Act,” he said.
The false positives that had emerged, Admiral Giroir said, were not only expected but “actually an outstanding result.” No test is perfect, he said.
In the Nevada statement, Dr. Azzam reaffirmed his concerns with the number of false positives that had arisen. “If this laboratory data discrepancy had been reported to Dr. Giroir, we would hope he would have taken the same action as Nevada,” he said. “We too want more testing with rapid turnaround in Nevada, but the results of those tests must be accurate, as they affect clinical care.”
The state’s nursing facilities can resume use of BD’s and Quidel’s products, according to a new Nevada directive issued on Oct. 9. But Nevada’s department of health also recommended that all antigen test results, positive or negative, be confirmed by a laboratory test that relies on a slow but very accurate and reliable technique called polymerase chain reaction, or P.C.R. False negatives, officials noted, risk exposing healthy people in nursing homes to someone who is unknowingly contagious. False positives, on the other hand, could prompt the placement of a person who is well into a unit with sick people, also increasing the chance of infection.
“Both of these scenarios could result in causing harm to a population that we have collectively worked so hard to protect,” the directive said. State health officials, it said, would also continue to investigate the use of BD’s and Quidel’s products.
“We need to better understand the issue before encouraging mass use of such tools among our most vulnerable citizens,” Dr. Azzam said. “We are not saying the tests have no use, we are just saying pause for further review and additional training.”
In a statement, Admiral Giroir said he and his colleagues were “pleased” about Nevada’s reversal. “This serves as a valuable public policy discussion that benefits the public interest by deterring unilateral prohibitions or similar actions in other states or jurisdictions,” he said.
Experts have previously raised concerns about rapid coronavirus tests, especially in situations where the products have been deployed on people without symptoms — an off-label use. Some have also pointed to the dangers of relying too heavily on rapid testing, as appears to have been the case at the White House, where dozens have been infected in an ongoing outbreak.
The federal government recently began distributing another brand of rapid antigen test for the virus, manufactured by Abbott Laboratories, by the millions to communities around the country, including nursing homes.
As the products come into even more widespread use, Dr. Fitzhugh of Rutgers University urged caution. When it comes to testing for the coronavirus, she said, “we cannot afford to be wrong.”