As at-home rapid tests enter the market, remember that ânegativeâ doesnât always mean negative.
A doctor sanitized between administering Covid-19 tests at a mobile testing unit in Sacramento.Credit.Max Whittaker for The New York Times
Dec. 23, 2020
Since the start of the pandemic, the Food and Drug Administration has issued emergency green lights to more than 200 types of coronavirus tests, each with its own curiosities and quirks. Yet we tend to talk about all of them in the same binary way, with identical terms: positive, negative, true, false.
But when it comes to interpreting results, not all positives and negatives are equally reliable. Factors like whether you had symptoms, or the number of people in your neighborhood who are infected, can influence how confident you should be in your results.
How Confident Can You Be in a Coronavirus Test?
Things like which kind of test it was, and the reason for taking it, should factor into how much credence to give a positive or negative result.
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In mid-November, David Piegaro tested positive for the coronavirus. His results came too late.
The night before, Mr. Piegaro, a member of the National Guard, drove to New Jersey to visit his family after receiving two negative rapid test results, two days in a row. By the next morning, he had left. But the single overnight stay was enough to spread the virus Mr. Piegaro was unknowingly carrying to multiple members of his family, including his grandfather, who ended up spending two weeks in the hospital.