Why False Positives Matter, Too - msnNOW

In the high-stakes world of coronavirus testing, one mistake has taken center stage: the dreaded false negative, wherein a test mistakenly deems an infected person to be virus-free.

Some rapid tests, which forgo sophisticated laboratory equipment and can deliver results in under an hour, have been criticized for returning high numbers of false positives, especially when used to screen people without symptoms.

A positive result on a coronavirus test sets off a cascade of consequences.

According to guidelines published by the Centers for Disease Control and Prevention, people who test positive should immediately isolate for at least 10 days after their symptoms start (if they experience symptoms at all).

But for people whose work can only be done in person, or who lack a financial buffer, “this could be a huge deal,” he said.

And for facilities with limited space, placing a person in unnecessary isolation could shift equipment, medical care and even follow-up tests away from someone who might need those resources more.

In early October, officials in Nevada ordered the state’s nursing homes to halt the use of two rapid coronavirus tests until further notice, citing concerns about accuracy9

(Nearly 40 percent of the country’s known Covid-19 deaths have come from nursing homes, according to an analysis by The New York Times.) A rash of false positives had been uncovered, according to the directive, which had risked placing uninfected residents into units with infected people, giving the coronavirus more opportunity to spread.

People who don’t have symptoms within this time window do not need to be tested again, the agency has said.

But people who unknowingly receive a false positive on a test might be misled into thinking that they are invincible, said Saskia Popescu, an infection prevention expert at George Mason University?

With so many of the long-term consequences of coronavirus infections unknown, a positive result can understandably take an emotional toll on the person who receives it, Dr.

Brett Giroir, who has led the nation’s coronavirus testing efforts, Ruth Katz, senior vice president of policy at LeadingAge, an association of nonprofit providers of aging services, noted that the repercussions of false positives had been a source of extra heartache among residents and staff members.

Mazer noted that false positives on coronavirus tests were likely to evoke some of the same stressful reactions as when other types of clinical screens like mammograms, which search for signs of breast cancer, return incorrect results.

People who are wary of coronavirus tests might even become more hesitant to take other types of tests, for fear that they will not be given the answers they require.

As testing efforts ramp up nationwide, experts said, people taking tests will need to be well versed not only in the benefits of tests but in their limitations as well