In the high-stakes world of coronavirus testing, an error has taken center stage: a frighteningly false negative, in which a test mistakenly considers an infected person to be virus-free.
Im Jim Wilson / The New York Times
Testing for coronavirus in San Francisco.
Experts say this troublesome outcome, which can deprive a person of treatment and mix them with others, hastens the spread of the disease.
But false negativity is not the only mistake to reduce coronavirus diagnostics. False positives, which incorrectly identify a healthy person as being infected with the virus, can also have serious consequences, especially in places where the virus is deficient.
However false positives seem relatively harmless compared to their false-negative cousins, “said Dr. Benjamin Mazer, a pathologist and diagnostics expert at Johns Hopkins University.” People can be completely injured. “
False positives are rarely found in tests checked by the Food and Drug Administration. But any test can suffer from contamination, absent or technical glitches, any device can detect coronavirus where it is not.
Some rapid tests, which leave sophisticated laboratory equipment and can yield results in less than an hour, have been criticized for returning a large number of false positives, especially when used to screen people without symptoms. Laboratory tests that rely on a very reliable technique called polymerase chain reaction, or PCR, are known to return occasional false positives.
In places where the virus is relatively rare, false positives may outweigh real positives – reducing confidence in tests and, in some cases, signaling their own outbreak.
Unnecessary isolation
A positive result on a coronavirus test, organizes a cascade of results. According to guidelines published by the Centers for Disease Control and Prevention, people who test positive should be separated at least 10 days after the onset of symptoms (if they all experience symptoms).
He spends 10 days with friends and family, and loses 10 days of potential productivity at school or work.
The ever-increasing availability of virtual platforms could make that transition easier for some, said Dr. Mazar said. But for those whose work can only be done face-to-face, or who don’t have the financial buffer, he said, “this could be a big deal.” “They could lose their paycheck. They could lose their jobs.”
Even caregivers find themselves in an precarious position by false positives, forcing them to separate themselves from children, elderly family members, or other sensitive contacts. If someone else needs to come and take their place, the risk of exposure to the virus may increase for everyone involved.
And for facilities with limited space, keeping an individual in unnecessary isolation can also replace equipment, medical care, and follow-up tests that require more of those resources.
New outbreaks
In certain circumstances, false positives can spawn new coronavirus cases. Crowd facilities, such as nursing homes, prisons or hospitals, can isolate coronavirus-positive people altogether.
The worst pathologist at Jersey University, Dr. “If someone is not really positive, we will send them to their death,” said Valerie Fitzgerald.
In early October, officials in Nevada ordered state nursing homes to stop using two rapid coronavirus tests until further notice, citing accuracy concerns. (According to an analysis by The New York Times, nursing homes accounted for about 40 percent of the country’s well-known Covid-19 deaths.) False positives were exposed as directed. Units with infected people are more likely to spread the coronavirus. Such a scenario could “harm a population we have collectively worked hard to protect,” officials noted in a follow-up note. Under pressure from the federal government, Nevada officials lifted the fast test ban on Oct. 9.
Missed or improper treatment
False positives can also be devastating in terms of treatment, said Lenoz Samuel, a clinical microbiologist at Henry Ford Health Systems in Detroit. People with the flu or Covid-19, for example, always show similar symptoms, but can only be tested for one of them at a time. If a patient is misdiagnosed with Covid-19, the person may be deprived of treatment that can alleviate their illness, or be given an expensive treatment that does little to speed up their recovery.
“It’s definitely the price you’ll pay,” said Dr. Samuel Samuel.
False sense of security
Large amounts of evidence suggest that most people who have fought the coronavirus once maintain a degree of immunity that can cause the virus to fail a second time. Scientists do not know how long this immunity lasts, or how it varies from person to person, but the CDC has issued guidelines stating that reorganization is not possible within 90 days. People who do not have symptoms in this time window do not need to be re-tested, the agency said.
It may be helpful advice for people who actually contracted coronavirus. Saskia Popescu, an infection prevention specialist at George Mason University, said people who inadvertently get false positives on a test will be misled into thinking they are invincible.
However, if these people were not really exposed to the virus, they would be just as susceptible as before – if not more so, they should choose to leave a mask or body spacing after assuming that their body has already been exposed to the virus. .
An infectious disease specialist at Louisiana State University, Dr. Catherine O’Neill expressed similar concerns this month when discussing the false-positive result given to University of Alabama football coach Nick Sub. Dr. “If anyone is excluded from routine testing, they will not just endanger their own health,” O’Neill said. False positives can put a whole group of close contacts at risk.
Improper stress
“Many of the long-term consequences of coronavirus infection are unknown,” said Dr. Fitzgerald. “A positive outcome can have an emotional impact on the person who understands it.” Can ‘, he said.
Adam. In a recent call with Brett Giroir, who has led the country’s coronavirus testing efforts, Ruth Katz, senior vice president of policy at Leadingage, an association of nonprofit providers of aging services, noted that it was a source of false positive results. Extra pain in residents and staff members
Dr. Mazar noted that false positive results on coronavirus tests are likely to produce similar stressful reactions while other types of clinical screens, such as mammograms detecting signs of breast cancer, give false results. “We see anxiety, frustration,” he said.
Losing faith in the test
As testing increases in the United States, experts have expressed concern that frequent and high-profile diagnostic errors can cultivate infatuation in the general population.
Tests with a reputation for any kind of false results can struggle to gain widespread traction. People who are wary of coronavirus tests may be more reluctant to take other types of tests for fear that they will not be given the answers they need.
More frequent and accessible testing is needed – but it can be more challenging to make it effective if people are less prepared to get involved, says Dr. Said the Major. “It can have long-term consequences.”
Because of these concerns and more, most specialists are encouraged to seek out more information on how to perform a variety of tests, outside of laboratories and clinics, at the point of diagnosis. Some tests are effectively healthy and will be able to be properly checked before they erupt before the quagmire erupts, while others are not suitable for this purpose. Depending on the circumstances, some tests may require their results to be confirmed with other, more accurate tests.
Testing Efforts Growing Nationwide Experts say that people taking tests need to be well-informed not only about the benefits of the tests but also about their limitations.
No exams are perfect, Fitzshu said. But, the tests, and the way in which they are arranged, must be thoroughly examined even before they are rolled out in large numbers. “People need to know that the tests they get are the best we’re going to offer.”
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