Within Internal Medicine, he directs the differentiation Bloodtransfusion Medicine. Next, Zwaginga is co-responsible for the LUMC-Sanquin Jon J van Rood Center for Clinical Transfusion Medicine Research, chairman of the Benign Hematologic Diseases working party of the Dutch Hematology Association and national ( HOVON ) JACIE representative and chairman of the stearing committee for the Blood transfusion guideline.