How does the search for a blood stem cell donor work?

Looking for a matching stem cell donor is like looking for a needle in a haystack. When a blood cancer or blood disorder patient depends on a blood stem cell transplant to survive, they need a donor whose tissue characteristics are a 100 percent match, if possible. Search requests are sent to the National Registry, and if a potential donor is found on the DKMS database, to match the patient, we will be informed and we will then contact the donor immediately.

Another problem is that even if a matching donor is found, they simply might not be available to donate at the specific point in time.