1. Department of Internal Medicine, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea.
2. Department of Gastroenterology, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea.
3. Department of Pathology, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea.
4. Department of Laboratory Medicine, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea.