Dan Xu1, Chao Han2, Mao-Shui Wang3, Jun-Li Wang4. 1. Department of Bronchoscopy, Shandong Provincial Chest Hospital, Jinan, China. 2. Department of Geriatrics, Shandong Mental Health Center, Jinan, China. 3. Department of Lab Medicine, Shandong Provincial Chest Hospital, Jinan, China; Department of Pediatrics, Qilu Hospital, Shandong University, Jinan, China. Electronic address: wangmaoshui@gmail.com. 4. Center of Clinical Laboratory, Affiliated Hospital of Youjiang Medical College for Nationalities, Baise, China. Electronic address: 13907768146@163.com.