"I'm also curious about the Anthony Nolan one....i registered many years ago.....wonder if our bone marrow us too old now"
The sample they took is analysed and key markers are noted. When someone needs a match, they look for people on the register who have those markers. A potential match is then retested, and the donation process is explained. Only if detailed testing confirms the best match, and the donor confirms consent, does it go ahead.
It really is a gift of life.