What does it mean to "swab"?
All that is required to join the bone marrow and stem cell donor registry is a cheek swab and a little paperwork. This cheek swab collects DNA that is sent to a lab and tested to find your 10 human leukocyte antigen (HLA) markers. This is the part of your DNA that must match up perfectly with the recipient if an unrelated transplant is to take place. This minimizes the risk of host vs. graft diseases which is essentially when the body recognized that the new organ/tissue is foreign and attacks itself.
Only about 1 in every 500 or 540 people swabbed is called to donate. About 1 in 300 may be called as a match and then not chosen to donate though. This is a great responsibility as patients get hope when they hear that they have an unrelated match in the donor pool. For this reason it is important to make sure that someone who swabs at a recruitment drive is sure that they will donate if called upon no matter who for and in either capacity. Remember quality over quantity when it comes to recruiting potential donors. Studies have shown volunteers who felt social pressure to join are most likely to withdraw if called upon anyways.