The Longitudinal Medical Record is used by our outpatient clinics to record clinical visit information such as history, notes, problems, medications, and allergies, and provides inpatient and outpatient test results, including imaging tests and laboratory blood tests, from 7 Partners-affiliated institutions: Brigham and Women's Hospital, Massachusetts General Hospital, Dana Farber Cancer Institute, Newton Wellesley Hospital, North Shore Medical Center, Faulkner Hospital, and Spaulding Rehabilitation Hospital. The Longitudinal Medical Record is especially useful for following patients who might undergo evaluation for a new problem, such as sudden onset of shortness of breath, at a suburban hospital such as Newton Wellesley Hospital, after a prior hospitalization at Brigham and Women's Hospital for treatment of a complicated medical illness with a high risk of VTE. In our 2005 randomized trial of electronic alerts for VTE prophylaxis,8 we relied upon the Longitudinal Medical Record to achieve 94% follow-up at 90 days of all patients enrolled at Brigham and Women's Hospital.