Department of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland. Institute of Clinical Chemistry, University Hospital Zurich, University of Zurich, Zurich, Switzerland. Department of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland; Center of Gastroenterology, Clinic Hirslanden, Zurich, Switzerland. Department of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland. Electronic address: PedroAntonio.Ruiz-Castro@usz.ch.