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Last week, the US Capitol had a huge problem which has since been overshadowed: @US_FDA flagged that the @Curative #COVID19 PCR tests it had been to screen entrants had more false negatives than expected. Here's what offices can learn to reopen safely: 1/x https://qz.com/work/1954140/what-types-of-covid-19-tests-could-be-used-to-reopen-the-office/
2/x The backstory: @Curative's #COVID19 PCR tests work like many others; they detect SARS-CoV-2 genetic material in quick swab. It returns results in 12 hours—which is fast for PCR! @US_FDA granted Curative an EUA in April; it also provides tests for big cities across the US.
3/x @US_FDA's warning last Mon. says tests have higher rate of false negatives, meaning someone could be told they don't have #COVID19 but they actually do. The risks are 1) that person misses out on treatment and 2) that person spreads the virus to others https://www.fda.gov/medical-devices/safety-communications/risk-false-results-curative-sars-cov-2-test-covid-19-fda-safety-communication
4/x It's not ENTIRELY surprising that this warning came out; if you look at Curative's EUA, the sample size they used for sensitivity/specificity wasn't very big huge. But also, that's pretty common for EUA Covid-19 tests; FDA was rushing to get tests out https://www.fda.gov/media/137089/download
(4.5 Quick refresher from @timmcdonnell and @AShendruk: Sensitivity = correctly ID'ing who is infected; specificity = correctly ID'ing who ISN'T infected.
https://qz.com/1941258/how-to-determine-the-accuracy-of-a-covid-19-test/)
https://qz.com/1941258/how-to-determine-the-accuracy-of-a-covid-19-test/)
5/x Aside from that, though, there was the problem with choosing to use a PCR test for workplace reentry to begin with. PCR tests were never meant to find Covid-19 patients among asymptomatic individuals; they're a diagnostic tool. @Curative's EUA makes this clear:
6/x Generally, PCR is regarded as the gold standard in Covid-19 diagnostics. But they're still an inferior choice for reopening a workspace.
1) They're expensive (~$100 each)
2) They take a while (12 hours = a person walking around all day)
3) They STILL have false negatives!
1) They're expensive (~$100 each)
2) They take a while (12 hours = a person walking around all day)
3) They STILL have false negatives!
7/x As @Michael_Hochman has told me before (and reminded me for this story), getting a negative #COVID19 PCR test doesn't mean much if you know/suspect you've been exposed. You'd still need to quarantine, even if you never develop symptoms https://qz.com/1905604/should-i-take-an-at-home-covid-19-test-to-hang-out-with-friends/
