[1] Univ Amsterdam, Emma Childrens Hosp AMC, Acad Med Ctr, Dept Pediat Hematol, NL-1105 AZ Amsterdam, Netherlands
[2] Univ Amsterdam, Acad Med Ctr, Lab Coagulat, Amsterdam, Netherlands
[3] Univ Amsterdam, Acad Med Ctr, Dept Clin Epidemiol & Biostat, Amsterdam, Netherlands