1. National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology, Beijing, P. R. China
2. Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, Beijing, P. R. China
3. Department of Infectious Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
4. Graduate School, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China