1. Department of Hematology, Cancer Center Amsterdam, Vrije Universiteit Medical Center, Amsterdam, The Netherlands;
2. Hemato Oncologie Volwassenen Nederland Data Center, Erasmus Medical Center Cancer Center, Rotterdam, The Netherlands;
3. Section of Hematology and Coagulation, Department of Medicine, Sahlgrenska University Hospital, Gotheborg, Sweden;
4. Department of Hematology, Rigshospitalet, Copenhagen, Denmark;
5. Department of Hematology, Maastricht University Medical Center, Maastricht, The Netherlands;
6. Department of Internal Medicine, Albert Schweitzer Hospital, Dordrecht, The Netherlands;
7. Division of Hematology and Transfusion Medicine, Skane University Hospital, Lund, Sweden;
8. Department of Internal Medicine, Martini Ziekenhuis, Groningen, The Netherlands;
9. Department of Internal Medicine, Tergooi Ziekenhuizen, Blaricum, The Netherlands;
10. Center of Hematology, Karolinska Institute, Stockholm, Sweden;
11. Department of Internal Medicine, Isala, Zwolle, The Netherlands;
12. Department of Hematology, Vejle Hopital, Vejle, Denmark;
13. Department of Internal Medicine, Meander Medisch Centrum, Amersfoort, The Netherlands;
14. Department of Internal Medicine, Groene Hart Ziekenhuis, Gouda, The Netherlands;
15. Department of Oncology, Hematology and Palliative Care, Førde Central Hospital, Førde, Norway;
16. Department of Internal Medicine, Reinier de Graaf Ziekenhuis, Delft, The Netherlands;
17. Department of Internal Medicine, Medisch Centrum Alkmaar, Alkmaar, The Netherlands;
18. Department of Internal Medicine, Maasstad Ziekenhuis, Rotterdam, The Netherlands;
19. Department of Internal Medicine, Jeroen Bosch Ziekenhuis, Den Bosch, The Netherlands;
20. Department of Hematology, Stavanger University Hospital, Stavanger, Norway;
21. Department of Internal Medicine, Zaans Medisch Centrum, Zaandam, The Netherlands;
22. Department of Internal Medicine, Tweesteden Ziekenhuis, Tilburg, The Netherlands;
23. Department of Internal Medicine, Rijnstate Ziekenhuis, Arnhem, The Netherlands;
24. Department of Genetics, Radboud University Medical Center, Nijmegen, The Netherlands;
25. Department of Hematology, Erasmus Medical Center Cancer Center, Rotterdam, The Netherlands; and
26. Department of Hematology, St Olavs Hospital and Norwegian University of Science and Technology and KG Jebsen Myeloma Research Center, Trondheim, Norway