How you prepare

If you want to donate stem cells, you can talk to your doctor or contact the National Marrow Donor Program, a federally funded nonprofit organization that keeps a database of volunteers who are willing to donate.

If you decide to donate, the process and possible risks of donating will be explained to you. You will then be asked to sign a consent form. You can choose to sign or not. You won't be pressured to sign the form.

After you agree to be a donor, you'll have a test called human leukocyte antigen (HLA) typing. HLAs are proteins found in most cells in your body. This test helps match donors and recipients. A close match increases the chances that the transplant will be a success.

If you sign up with a donor registry, you may or may not be matched with someone who needs a blood stem cell transplant. However, if HLA typing shows that you're a match, you'll undergo additional tests to make sure you don't have any genetic or infectious diseases that can be passed to the transplant recipient. Your doctor will also ask about your health and your family history to make sure that donation will be safe for you.

A donor registry representative may ask you to make a financial contribution to cover the cost of screening and adding you to the registry, but this is usually voluntary. Because cells from younger donors have the best chance of success when transplanted, anyone between the ages of 18 and 44 can join the registry for free. People ages 45 to 60 are asked to pay a fee to join; age 60 is the upper limit for donors.

If you're identified as a match for someone who needs a transplant, the costs related to collecting stem cells for donation will be paid by that person or by his or her health insurance.