Count­ries whe­re the­re are many insti­tu­ti­ons working in the field of stem cell dona­ti­on and trans­plan­ta­ti­on usual­ly have a cen­tral regis­try (hub) which coor­di­na­tes and faci­li­ta­tes the com­plex pro­ces­ses of sear­ching for donors and trans­plan­ta­ti­on. In Ger­ma­ny, this task was trans­fer­red to the ZKRD (Ger­man Natio­nal Bone Mar­row Donor Regis­try) in 1992. The search-rele­vant data from all vol­un­t­a­ry donors regis­tered with the regio­nal and natio­nal donor cen­ters in Ger­ma­ny is coll­ec­ted anony­mously at the ZKRD. During a donor search, this data is com­pared against that of the pati­ent in ques­ti­on and the search cen­ter is infor­med of the poten­ti­al­ly sui­ta­ble donors. Based on their roles, a distinc­tion is made bet­ween regis­try and donor cen­ter even if some donor cen­ters include the word “regis­try” in their offi­ci­al titles.