1. The Central Facility, ECAA, Department of Pathological Sciences, The University of Manchester, UK
2. Division of Haematology, National Institute for Biological Standards and Control, UK
3. Haemostasis and Thrombosis Research Centre, Leiden University Hospital, The Netherlands
4. Department of Clinical Biochemistry, Centralsygehuset, Esbjerg, Denmark
5. A Bianchi Bonomi Hemophilia and Thrombosis Centre, University & IRCCS Maggiore Hospital, Milan, Italy