i'm kristin tsay. new research says impact of long covid can now be detected with 94% accuracy. joining us live now to talk about it is pj utts, professor of medicine at stanford university, to discuss this new development in detecting the post virus disease . thank you so much for joining us, professor woods. >> yeah, thank you so much for having me. >> so how do you define long covid and what percentage of people who get covid actually suffer from these prolonged symptoms? >> so long covid has it's a very heterogeneous disorder with a complex, a complex way to describe it. there's more than one definition in. so typically, you have to have symptoms for an extended period of time after having been infected with sars-cov-2. and there are protean manifestations, brain fog, myalgias and so forth. a large you know, there's a debate about how many people actually end up getting long covid, but it's estimated to be somewhere between at least ten and 20 million people in the united states. >> i see. okay. well, let's talk about in the research published monday in the journal nature sc