Abbre­via­ti­on for Bone Mar­row Donors World­wi­de based in Lei­den, Nether­lands. Con­den­sed data on all donors world­wi­de is collec­ted by the BMDW at regu­lar inter­vals. When the search for a donor begins, it is rela­tively easy to deter­mi­ne from this glo­bal data­ba­se how many poten­ti­al donors the­re are for the pati­ent in ques­ti­on and in which regis­try. A spe­ci­fic request for the detail­ed data of the respec­ti­ve donors can then sub­mit­ted to the natio­nal registries.