Also in this case, legislation varies from country to country and the best way to gather precise information is to consult the website of your national bone marrow donor association (see the registries page). In general, the donor is examined by means of analysis of a blood sample or a saliva sample or a fragment of skin.
The results of the analysis will then be stored in a national electronic database, connected itself to other national databases to form a world-wide pool. It is within this database that possible compatible donors are found for patients awaiting transplant, are then called to undergo further and more detailed analysis to check the grade of compatibility.
At this point the commitment of the donor plays a major role: the agreement the donor signs at the time of the first blood analysis is not binding and the donor can, at any moment, decide not to carry on with the procedure, with obvious consequences on the hopes of the patient and his family.
All these considerations clarify the fact that the bone marrow donor is an atypical donor, who offers some of his hematopoietic stem cells, obtained in a safe way within the closest authorized centre, in the very rare case that a compatible patients is waiting for transplant. His commitment is free and anonymous, is not stopped by geographical borders. The donor, in fact, becomes part of the world wide community of bone marrow donors.
It is also important to stress that, most of the time, the selected donor is the only one compatible with a certain patient in a certain moment, throughout the whole world. Often, he is the only possible salvation.