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. Peking University Fifth School of Clinical Medicine, Beijing, P. R. China
3. Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, Beijing, P. R. China
4. Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China