There are two different ways to obtain stem cells for transplantation.
In the case of peripheral blood stem cell donation, the donor is given a growth factor for
several days to encourage the stem cells to mature faster and pass into the blood. The stem
cells are then filtered out of the blood in a similar way to dialysis. Since this has now become
the standard method, we no longer tend to talk about bone marrow transplants but rather
(blood) stem cell transplants.
With a bone marrow donation, a long needle is used to extract some of the bone marrow from
the pelvic bone of the donor under general anesthesia. The bone marrow is quickly
regenerated by the body.