Beijing Friendship Hospital Affiliated to the Capital Medical University;
Beijing 100050;
China;
Department of Gastroenterology;
Qingdao Municipal Hospital;
Qingdao 266071;
Shandong Province;
China;
Department of Gastroenterology;
Beijing Friendship Hospital Affiliated to the Capital Medical University;
Beijing 100050;
China;
Shuo Yang;
Laboratory Medicine Department;
Peking University Third Hospital;
Beijing 100050;
China;