Dark Canyon Laboratories, LLC, Rapid City, South Dakota, USA. Department of Internal Medicine and Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA. Division of Gastroenterology, Massachusetts General Hospital, Boston, Massachusetts, USA. Division of Gastroenterology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA. Division of Gastroenterology, Department of Medicine, Center for Endoscopic Education, Innovation, and Training, Departments of Medicine and Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.