1. College of Medicine and Pharmaceutics, Ocean University of China, Qingdao, Shandong, China
2. Department of Gastroenterology, Qingdao Municipal Hospital, Qingdao, Shandong, China
3. Medical College, Qingdao University, Qingdao, Shandong, China
4. Central Laboratories, Qingdao Municipal Hospital, Qingdao, Shandong, China