How false negatives are complicating COVID-19 testing

Washington – As COVID-19 tests become more widely available across the U.S., scientists have warned about a growing concern: Many people with negative results might actually have the virus. That could have devastating implications as a global recession looms and governments wrangle with the question of when to reopen economies shuttered with billions of people ordered to stay home in an effort to stop transmissions of the deadly disease. The majority of tests around the world use a technology called PCR, which detects pieces of the coronavirus in mucus samples. But "there are a lot of things that impact whether or not the test actually picks up the virus," said Priya Sampathkumar, an infectious diseases specialist at Mayo Clinic in Minnesota. "It depends on how much virus the person is shedding (through sneezing, coughing and other bodily functions), how the test was collected and whether it was done appropriately by someone used to collecting these swabs, and then how long it sat in transport," she said.