but president vergy, thank you so much. i appreciate your time. and thank you for what you're doing. we'll check back in. >>> just into cnn, a new study raising questions about a coronavirus test used by the white house and touted by the white house. cnn medical correspondent elizabeth cohen is back with us. elizabeth, what is this? >> so even before the study there were other studies that called into question the accuracy of this abbott test, the one that the white house is using on its staffers, sometimes daily, to make sure they don't infect each other or the president. and what they found was that when they compared it to another test, that the abbott test missed half of the positive specimens, they said they were negative. and according to this study it looks like they know they're positive because the other test said they were positive and the people had symptoms of covid-19. so one doctor i talked to and infectious disease specialist said maybe it is time to look again and see if there is another test to use. the advantage of the abbott tes