1. Clinical Laboratory, Linyi Central Hospital, Linyi, Shandong�276400, P.R.�China
2. Nursing Department, Traditional Chinese Medicine Hospital of Yangxin, Binzhou, Shandong�251800, P.R. China
3. Digestive Endoscopy Room, Weifang People's Hospital, Weifang, Shandong 261041, P.R.�China