BRISBANE, Calif.--(BUSINESS WIRE)--XDx, Inc., a molecular diagnostics company focused on noninvasive gene expression tests for the monitoring of immune-mediated conditions, today announced that Pierre Cassigneul, president and chief executive officer, is scheduled to present at the Thomas Weisel 2009 Healthcare Conference on Thursday, September 10, 2009 at 2:40 p.m. (EDT) at the Four Seasons Hotel in Boston.