Beck the procedure may be different now but years ago when I registered, the blood bank gave my details to the Australian Bone Marrow Donor Registry and they kept it on file. This was done at a regular blood donation.

Also not sure if there have been any updates to this, but I hope someone will correct me if so. My understanding is that the bone marrow donor is put under general anaesthetic to remove the marrow. They generally take it from the hip bone so you will need to be under as the procedure would be too much if awake. You will feel a bit sore for a few days but up and about very soon. Your body will quickly manufacture more marrow to replace the amount you have donated.

The recipient in the meantime has had a massive dose of radiation to kill off their own diseased bone marrow. They are then essentially without immunity so are kept in isolation while waiting for the donation. Your harvested bone marrow is then delivered to them via a line in the arm (for want of a better description). Apparently, the marrow is able to find its way to the bones and set up shop so the patient can start from scratch with new disease free bone marrow.

Hopefully the patient's body will not reject the marrow and they will go on to a full recovery, basically free of the fear that the leukaemia will return because with the new marrow, relapse is not an issue anymore.

Anyway, if you are thinking about it, have a chat to the people at the blood bank when you go. They should be able to give you some information.