1 Department of Haematology, Tan Tock Seng Hospital, Novena 308433, Singapore; Department of Laboratory Medicine, Khoo Teck Puat Hospital, Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Singapore. Electronic address: bingwen_eugene_fan@ttsh.com.sg.