1. Department of Respiratory Medicine, The Second Hospital of Shandong University, Jinan, Shandong 250033, P.R. China
2. Department of Emergency Internal Medicine, Jining First People's Hospital, Jinning, Shandong 272000, P.R. China
3. Clinical Medical Laboratory Center, Jining First People's Hospital, Jinning, Shandong 272000, P.R. China