1. From the Department of Laboratory Medicine (Tan, Saw, Chew, C. Wang, Pajarillaga, Khoo, W. Wang, Ali, Yang, Jureen, Sethi), National University Hospital, Singapore
2. The Biostatistics Unit, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (Chan)
3. The Division of Infectious Diseases (Tambyah), Department of Medicine, National University Hospital, Singapore