Forty percent of U.S. Covid-19 tests come back too late to be clinically meaningful, data show
CNBC and Dynata ran a survey of more than 9,400 Americans in all 50 states to get a sense of testing turnaround times for Covid-19. Experts say results need to be returned in less than three days, optimally two, to be clinically meaningful. The results showed almost 40% of tests take longer than that.
In early July, Shannon Mayer started to feel a sudden tightness in her chest. “The next day it was really hard to breathe,” the 31-year-old Chicago resident told CNBC. “I got scared.” Mayer has asthma, but says she hadn’t had an issue with it for years. So she decided to get a test for Covid-19. The results, she was told, would take five to 10 days, and she was instructed to quarantine while she waited. After a week, the results still hadn’t been returned. And Mayer already felt better and suspected she wasn’t infected, so she stopped quarantining. “Had I stuck with it, I would have been in my house for three weeks,” she said. She was tested July 1, and her results didn’t come back until July 24. Luckily, she was negative. Mayer’s not alone. Bethany Silva, who lives in New York City, reported a 13-day wait for her results. For Lisa Miller, in New Jersey, it was a week.
Health experts say two days or less is optimal for returning Covid-19 test results to make them useful for stopping transmission. If test results take more than three days, people are unlikely to self-quarantine and getting in touch with the people they interact with during that time — potentially spreading virus — can be difficult. “It’s really clear that if tests take more than 48 hours, you’ve lost the window for contact tracing,” Dr. Ashish Jha, professor of global health at Harvard University, said in an interview. “I think, basically, beyond 72 hours, the test is close to useless.” A survey run by CNBC in partnership with Dynata, a global data and survey firm, suggests almost 40% of Americans had to wait more than three days for their results, rendering them — by Jha’s definition — useless. That’s certainly the way Mayer felt. “The whole purpose is to find out if I have it before it’s over,” Mayer said. “So that just completely defeated the purpose.”
The results varied state by state. Some, like Massachusetts and South Dakota, had average turnaround times of just over two days. Others, like Arizona and West Virginia, were closer to four and a half days, on average. Indiana’s average test turnaround time was more than five days. Jha said the variation is evidence of a fragmented testing strategy in the U.S. “It would take a national testing strategy to make sure that, if there’s excess capacity in Massachusetts, but long lines in Florida, that Massachusetts could help Florida out,” Jha said. “Largely we have not had a national testing strategy. The strategy out of the White House has been for every state to figure this out on their own.” Even national labs struggled to keep up with demand when cases were surging across the Sunbelt, with Quest Diagnostics saying in mid-July that its turnaround times were more than a week for non-priority patients. It has since said it’s increased capacity and that results now take an average of two to three days.
Admiral Brett Giroir, the Trump administration’s Covid-19 testing czar, told NBC’s Andrea Mitchell this week that results that take seven to 14 days are outliers. “In general, if you do need a test — you fall in the categories of needing a test, even for public health tracing — you’re going to get that result within 48 to 36 hours,” he said. Not everyone needs tests, Giroir said, and the national testing approach is “strategic testing, not shotgun testing,” which he said has reversed the outbreaks in that region. Indeed, new daily cases declined by 44% in Florida from a mid-July peak, while they’re down 73% in Arizona, both on a seven-day average, according to the Covid Tracking Project, a data source run by journalists at the Atlantic.
https://www.cnbc.com/2020/08/15/forty-percent-of-us-covid-19-tests-come-back-too-late-to-be-clinically-meaningful-data-show.html