naGateway Gastroenterology 121 Saint Luke's Center Drive, Suite 406, Building A, Chesterfield, MO 63017naMain Office Location121 Saint Luke's Center Drive, Suite 406, Building AChesterfield, MO 63017 Monday: 8:00 AM - 4:00 PM Tuesday: 8:00 AM - 4:00 PM Wednesday: 8:00 AM - 4:00 PM Thursday: 8:00 AM - 4:00 PM Friday: 8:00 AM - 4:00 PM Saturday: Closed Sunday: Closed