OLYMPIA — A bill to help hospitals significantly reduce the high costs of storing outdated medical records was signed into law Tuesday. Senate Bill 5239, sponsored by Sen. Vandana Slatter (D-Bellevue), passed the Legislature with bipartisan support.   Right now, hospitals are required to keep medical records for 10 years after a patient’s discharge. If there’s no official discharge date, hospitals must keep the records indefinitely — something that’s been proven costly and hard to manage.   "I have heard from hospitals such as the University of Washington (UW) Medical Center that are storing records from the 1950s,” Slatter said. ...