When people join Gift of Life as potential stem cell or marrow donors, they often do so at a drive to help a specific patient find a match for a transplant.  Many of them hope that they will be called within days or weeks to help that patient, then months go by and the call doesn’t come.  Why not?  

Many people believe that donating stem cells is like a blood transfusion – if it turns out they have the same blood type, they’ll be able to help that person in need.  But, transplanting stem cells or marrow is not as straightforward as doing a blood transfusion. 

For a blood transfusion, there are only eight possible blood types to match. However, blood type has nothing to do with stem cell and marrow transplants, and finding a matching donor is much more complex.  

Matches for stem cell and marrow transplants are based on genetic factors found in the immune system, the Human Leukocyte Antigens (HLA). With tens of millions of possible HLA combinations, it is difficult – but not impossible – to find another human with the exact same profile.

The highest chance of a match is within the family: there is a 25% chance of each individual sibling being a match for one another. About 30% of patients are able to find a match within their family. The other 70% must search the registry in the hopes of finding someone who shares the same HLA profile. 

The best chance of finding an unrelated match is with a person who has similar ancestry – someone from the same ethnic group or genetic heritage – and the more people who join the registry the more likely matches will be found for everyone in need. 

Although the rarity of two people having the same HLA profile makes it unlikely, although not impossible, that you will be an exact match for your friend, by joining the registry, you still have the chance to become a hero and save a life. Simply by being in the registry, you increase the pool of possible donors and may match someone else who needs your help to survive blood cancer or another disorder. 

Every donor has the potential to save someone's life, and help them stay with their family, see more of life's milestones, remain an important part of their community. When you save one life, it isn't just one life – it's a whole world of people who are also saved. 

Not in the registry yet? If you are 18-35 and in general good health, click here to order a cheek swab and registration kit sent to your home.