In Special issue 5 of 2015 P. Meijer (1), I. van Moort (2) , M. H. Cnossen (2) and M.P.M. de Maat (3) (1 ECAT Foundation, Leiden, 2 Erasmus University Medical Center – Sophia Children’s Hospital, Rotterdam, 3 Erasmus University Medical Center, Rotterdam) described the external quality assessment for Factor VIII and Factor IX.
