The thing that it's hard to get across sometimes is that registering as a bone marrow donor and donating bone marrow are two separate processes.
When you register, you're providing a blood sample (or, depending on where you live, a cheek swab) from which the registry records part of your HLA (human leukocyte antigen) typing.
When someone is searching the registry for a compatible donor, what they're searching for is someone who has registered and matches those HLAs. If those first HLAs line up, it indicates the possibility that the two people are compatible.
If it turns out that all of the HLAs match and the potential donor agrees, then there's the actual donation, which is either a collection of stem cells (much like a blood draw) or an extraction of liquid bone marrow, depending on the needs of the patient.
That's it in a nutshell. We have much more information, including a list of international registries and information on some of the issues regarding transplants at healemru.com.
Thank you for taking the time for explaining and clarifying all of that. Very much appreciated and we are all wiser now.
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