“Tested Positive for Coronavirus Antibodies? Don’t Let Your Guard Down” - Brianna Abbott, Elbert Wang and Denise Roland
Those who have tested positive for coronavirus antibodies shouldn’t let their guard down, as many tests have been proven inaccurate, and it’s not certain that antibodies guarantee immunity. For some of the most accurate tests—those with greater than 99.5% specificity, like the ones developed by Roche Holding AG and Mount Sinai Hospital in New York—the positive predictive value is still above 90% at 5% prevalence, so false positives are rarer. For a handful of tests, though, the positive predictive value drops to around 50%.