across the nation are testing the limits of testing centers. i was supposed to go home to florida tomorrow, and a bunch of people were testing positive. reporter: in states like new york, california and florida the testing got shut down. reporter: sites are overwhelmed and out of stock. every two, three weeks, me and my wife we get tested just in case. reporter: facing crushing demand, the mayor of new york city is calling on the president to invoke the defense production act, requiring private companies to ramp up test production. this whole country needs to go on a war footing to fight back. having enough test kits when we need it, having enough treatment when we need it is key. and that s what we need the federal government s help with reporter: after at least three states began handing them out for no cost. i get it for free, so i love it. reporter: tonight in several cities, at home test kits are nearly impossible to find pharmacies confirming an unprecedente