GREY'S ANATOMY - "What a Difference a Day Makes" - Bailey, Izzie and Derek look at some of Izzie's test results, on "Grey's Anatomy," THURSDAY, MAY 7 (9:00-10:02 p.m., ET) on the ABC Television Network. (ABC/SCOTT GARFIELD) CHANDRA WILSON, KATHERINE HEIGL, PATRICK DEMPSEY