This study is set up as a first step of implementing patient blood management (PBM) in this hospital. PBM is an evidence-based, multidisciplinary approach to optimizing the care of patients who might need transfusion. Not only in pre/per/postoperative setting but also in haematology PBM guidelines can be implemented. Examples are: use of a restrictive haemoglobin trigger for red blood cells (RBC) transfusion, single use policy for the administration of RBC and platelets, administration only for correct indications (including the introduction of an electronic clinical decision support system for ordering blood components), ...