False Positives

Point of Care Tests

Another catastrophe. The Trump administration expanded cheap testing in long-term care settings sending thousands of point-of-care testing systems to nursing homes. The goal was to allow facilities to quickly detect new Covid-19 cases among residents and staff. The effort to arm nursing homes with rapid coronavirus tests is failing because the tests return false positives.

For example, Nevada ordered nursing homes to stop using the point-of-care tests after more than 20 instances of false positives. More than half of the positive samples re-tested. Other states are now questioning their accuracy as well. ABC News discovered that Connecticut, Arkansas, New Jersey, Wisconsin and Minnesota use polymerase chain reaction (PCR) testing in long-term care facilities.

The Trump Administration may sue claiming states don’t have the authority to bar the tests. False positives are unavoidable, particularly when screening tests are widely deployed. “This is not a problem of false positives,” USDHHS added. “This is really a reality of false positives being a part of the testing ecosystem.”

False Results

The rapid antigen tests works in 15 minutes but it is not accurate. They also don’t require a lab to process and are cheaper. But a well-established limitation is that they can return false negatives, missing people who are infected.

Now the concern has emerged around false positives. This result may move them to Covid-19 wards when they’re not infected.

“Then they go and get Covid,” said Jeff Engel, senior adviser at the Council of State and Territorial Epidemiologists, or CSTE. “We think there’s a lot more work that needs to be done on accuracy” of point-of-care tests.

CSTE has heard about false positives in almost every state. Manufacturers of the screenings and Trump’s henchmen claim that false positives occur with all tests. The government, though, is pushing to expand rapid testing more broadly, including in schools.

Experts recommend isolating long-term care employees or residents following a positive antigen test, while awaiting confirmation from a PCR test.

The CDC says that nursing homes using antigen testing should confirm a positive result for an asymptomatic individual with a PCR test within 48 hours, especially if the county has low virus rates.