The investigators noticed a variable prescription of blood components to haematological patients in the hospital. This study will analyze the prescription and administration of blood components to Haematological patients (pre measurement). Based on these results guidelines on transfusion triggers will be updated and educated to the physicians and new ICT (information and communications technology) implementations will be added to the electronic order for blood components. The investigators hope to see afterwards (post measurement) a more stable prescription and administration of blood components and a more economic use of blood components.