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    Health Promotion and Chronic Disease Prevention Section
    MC 1965
    PO Box 149347 Austin, TX 78714-9347
    1100 West 49th Street
    Austin, TX 78756

    Phone: (512) 458-7111
    Fax: (512) 458-7618


Donor Eligibility

If you’re between the ages of 18 and 40, committed to donating to any patient in need, and meet the medical guidelines, you can register to be a bone marrow donor

Patients especially need you if you’re between the ages of 18 and 35. Research shows that cells from younger donors lead to more successful transplants. Doctors request donors in the 18 to 35 age group nearly 75 percent of the time.

Are you under the age of 18? Sign up for the Under 18 Pre-Registry . You’ll receive a reminder to join the registry when you’re eligible.

The Need for Ethnically Diverse Donors

Saving lives through a bone marrow transplant requires matching human leukocyte antigen (HLA) types. HLAs are proteins, or markers, found on most cells in your body. Since these HLA markers are inherited, patients in need of a transplant are more likely to find a match with donors who share their ethnic background.

Because of the lack of diversity on the registry, not every patient has the same chance of finding a compatible donor. The numbers below represent the likelihood patients have of finding a match based on their ethnic background:

  • Asian or Pacific Islander: 47 percent
  • Black or African American: 29 percent
  • Hispanic or Latino: 48 percent
  • Native American: 60 percent
  • White: 79 percent

Disparity_Graphic_Standard_Short_2021-05-21

Patients of mixed ethnicity also have a significantly lower chance of finding a match.

To increase diversity on the registry, we need more people with ethnically diverse backgrounds to join it.

How Donors and Patients Are Matched

Matching donors and patients is much more complex than matching blood types. Doctors match donors to patients based on their human leukocyte antigen (HLA) tissue type. HLA are proteins, or markers, found on most cells in your body. Your immune system uses these markers to recognize which cells belong in your body and which do not. A close HLA match between donor and patient is the most important matching factor.

HLA Typing

People have many HLA markers. Half are inherited from their mother and half from their father. This means that each brother and sister who shares the same parents as a patient has a 25 percent chance of being a close HLA match. Extended family members are not likely to be close HLA matches. About 70 percent of patients who need a transplant won’t have a fully matched donor in their family.

Research has found that a donor must match a minimum of six HLA markers. Many times, a closer match is required. The best match is found through detailed testing. Because some HLA types are less common than others, some patients may face a greater challenge in finding a matching donor. Some HLA types are found more often in certain racial and ethnic groups.

A close match between a donor’s and a patient’s HLA markers is essential for a successful transplant outcome. HLA matching promotes the growth and development of new healthy blood cells (called engraftment) and reduces the risk of a post-transplant complication called graft-versus-host disease (GVHD).

HLA matching


Factors in Matching

There are two important factors in matching marrow donors to patients: ancestry and age.

Ancestry: Your HLA—your tissue typing—is inherited. This is why patients are most likely to match someone of the same ethnic background. Adding more members who increase the ethnic diversity of the registry increases the variety of tissue types available. This helps more patients find the match they need.

Age: Potential donors are listed on the registry until their 61st birthday. However, doctors request donors in the 18 to 35 age group nearly 75 percent of the time. Research shows that younger donors provide the greatest chance for transplant success. 

Likelihood of Being a Match

Every person who joins the registry gives patients hope, and new patient searches begin every day. If you have a relatively common tissue type, you might be one of many who could match a searching patient. If you have an uncommon tissue type, you may never match a patient, or you might be the only 1 out of more than 39 million potential donors worldwide who can be someone’s cure.

Because our bodies replace lost bone marrow after donation, you could, in theory, be called to donate again. However, being a match for more than one patient is rare.


Last updated February 17, 2022