Dear Mayo Clinic: What's involved in becoming a bone marrow donor?

Answer: A person can become a bone marrow donor in two ways. One is to donate to someone you know, usually a family member, who needs a bone marrow transplant. The second is to have your name listed on a national registry of willing bone marrow donors. This registry is used when people who need a bone marrow transplant cannot find a relative who is a compatible donor. Bone marrow donation previously involved a minor surgical procedure, but a less-invasive technique is now used most often.

Although the procedure is called a bone marrow transplant, it is actually the blood-forming (hematopoietic) stem cells within bone marrow that benefit the transplant recipient.

People who need a bone marrow transplant often have blood disorders such as leukemia, lymphoma or severe anemia.

To be a bone marrow donor, you must have stem cells in your bone marrow that match the recipient's.

If you are accepted as a donor, a procedure is performed to gather your stem cells. In the past, that involved minor surgery to draw approximately 1 to 1.5 quarts of bone marrow from your hip bones. Stem cells were collected from the donated marrow. Now, that process is used less frequently.

Today, blood-forming stem cells are more often collected by filtering them directly from your bloodstream. Before the procedure, you're given a daily medication for five days to stimulate production of stem cells, so more of them are circulating in the bloodstream, and they can be easily separated from the rest of the blood.

After your donation, the recipient receives the stem cells through a process similar to a blood transfusion.

Bone marrow donors are always needed. The National Marrow Donor Program maintains a registry of potential donors from across the United States. You can find more information at the program's Web site at marrow.org.

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