1. Department of Pediatrics; Aarhus University Hospital Skejby; Denmark
2. Department of Pediatrics; Umeå University Hospital; Umeå Sweden
3. Institution for Clinical Sciences, Department of Pediatrics; Queen Silvia Children's Hospital; Gothenburg Sweden
4. Department of Pediatrics; Queen Mary Hospital and Hong Kong Pediatric Hematology & Oncology Study Group (HKPHOSG); Hong Kong China
5. Department of Pediatrics; University Hospital; Lund Sweden
6. Children's Hospital, University of Helsinki and Helsinki University Central Hospital; Helsinki Finland
7. Department of Pediatrics; Landspitalinn; Reykjavik Iceland
8. Department of Pediatrics and Adolescent Medicine; Rigshospitalet, University of Copenhagen; Copenhagen Denmark
9. Department of Woman's and Children's Health; Uppsala University; Uppsala Sweden
10. Division of Pediatric and Adolescent Medicine; Oslo University Hospital; Oslo Norway
11. Department of Clinical Chemistry and Transfusion Medicine; Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg; Gothenburg Sweden