A report in Kaiser Health News by Rachana Pradhan explored problems with certain rapid COVID-19 tests. In mid-May, the U.S. Food and Drug Administration (FDA) issued a rare public warning about an Abbott Laboratories COVID-19: Test results could be wrong.
The agency at that point had received 15 “adverse event reports” about Abbott’s ID NOW rapid COVID test suggesting that infected patients were wrongly told they did not have the coronavirus, which had led to the deaths of tens of thousands of Americans. The warning followed multiple academic studies showing higher “false negative” rates from the Abbott device, including one from New York University researchers who found it missed close to half of the positive samples detected by a rival company’s test.
But then, in a move that confounded lab officials and other public health experts, a senior FDA official later that month said coronavirus tests provided outside lab settings would be considered useful in fighting the pandemic even if they miss one in five positive cases — a worrisome failure rate.
The FDA has now received a total of 106 reports of adverse events for the Abbott test, a staggering increase. The agency has not received a single adverse event report for any other point-of-care tests meant to diagnose COVID-19, an agency spokesperson said.
In a statement, Abbott Laboratories said the NYU research was “flawed” and “an outlier,” citing studies with higher accuracy rates.
The Abbott rapid test is one of over 100 COVID-19 diagnostic tests to receive FDA emergency use authorization during the pandemic. In its own COVID-19 testing policy for labs and commercial manufacturers, the FDA says a diagnostic test should correctly identify at least 95% of positive samples.
But medical professionals are split over the lower 80% threshold for the Abbott and other point-of-care tests’ “sensitivity” — a metric showing how often a test correctly generates a positive result. They are debating whether it’s sufficient, given the risks that an infected person unwittingly spreads COVID-19 after receiving a negative result.
False negatives increase the risk that patients will not self-isolate or exercise other precautions — such as wearing a mask — and make more people sick than if they had had an accurate diagnosis. Evaluations of the Abbott test have been among the most mixed, with some researchers finding that the test has bigger accuracy problems, but others saying it isn’t likely to miss sicker patients.
“There’s no way I would be comfortable missing 2 out of 10 patients,” said Susan Whittier, director of clinical microbiology at New York-Presbyterian/Columbia University Medical Center. Whittier and co-authors found that the Abbott test correctly identified 74% of positive samples compared with a test from Roche, another diagnostics giant. A point-of-care test from Cepheid, a rival company, correctly identified 99% of positives.
In a statement, Abbott said when its test is used as intended it “is delivering reliable results and is helping to reduce the spread of infection in society by detecting more positive results than would otherwise be found.” Studies from University Hospitals Cleveland Medical Center and OhioHealth found that its test detected at least 91% of positives.
In March, HHS officials announced that Cepheid would receive approximately $3.7 million through its Biomedical Advanced Research and Development Authority for coronavirus diagnostic development work; the Strategic National Stockpile also made a one-time $2.3 million purchase of Cepheid’s point-of-care tests, according to an agency spokesperson.
“Knowing the true performance of such a point-of-care test and knowing that it may be less sensitive than a central lab molecular test is important, but also can play a role in triaging patients who are suspected of having COVID-19,” Dr. Timothy Stenzel, director of the FDA’s Office of In Vitro Diagnostics and Radiological Health, said on the call when discussing the Abbott warning. “If we are able to determine that sensitivity of the assay in controlled trial circumstances is at least 80%, we feel like that test has a valuable place going forward in this pandemic.”
Until the FDA can complete post-market studies to verify performance, he said, negative results with the Abbott rapid test will be treated as “presumptive” negatives.
Despite that note of caution, governors were also told during a June 3 call with Vice President Mike Pence that the fast Abbott test should be used to test residents and staff in long-term care settings, according to two sources with knowledge of the discussions. As of May 31, more than 95,000 people in nursing homes have tested positive for COVID-19 and nearly 32,000 have died, according to the Centers for Medicare & Medicaid Services. If 20% of tests are false negatives, personnel with COVID-19 could be going about their normal activities, spreading the virus.
No test is perfect, whether it’s for a common illness like the flu or for COVID-19, which has killed nearly 120,000 Americans. Federal officials contend that the trade-off with point-of-care tests — especially ones as fast as Abbott’s, which can turn around a positive result in as little as five minutes and a negative one in 13 minutes — is that the tests can be used in spots where traditional lab tests aren’t as accessible. There’s also a greater risk of operator error when administering the test in the real world given the way patient specimens are collected and handled.
