Widespread COVID-19 testing is essential to safely reopen the US. While test availability has been the main focus, test accuracy may prove to be the bigger issue. If a test erroneously delivers a negative result, an asymptomatic person may continue interacting with people believing they are not infectious. While debate has focused on the accuracy of antibody tests which identify prior infection, diagnostic testing identifying current infection has received less attention.  The Diagnostic Challenge Diagnostic test inaccuracy can take the form of a false negative or a false positive result. A false positive erroneously identifying a person as infected has minor consequences including unnecessary quarantine and contact tracing. False negative results, however, are more consequential, because infected persons, including those who are asymptomatic, are not isolated or quarantined when they should be making them free to potentially infect others. Inaccuracy is particularly dangerous for antibody tests relied on to determine whether persons are immune. In this case, false positives are the chief threat by emboldening people who are not actually immune to believe and act as if they were. Moreover, even antibody tests capably of accurately identifying previous infections remain an iffy proposition for reopening purposes to the extent that […]