Sue Pavord, FRCP, FRCPath, is a consultant hematologist at Oxford University Hospitals NHS Foundation Trust and Associate Senior Lecturer in Medicine at the University of Oxford. Beverley Hunt, FRCP, FRCPath, MD, is Professor of Thrombosis and Haemostasis at King's College London, and is a consultant in the Departments of Pathology and Haematology at Guy's and St Thomas NHS Foundation Trust.