Being an Unrelated Donor

Each year, thousands of people donate bone marrow or stem cells to give a complete stranger a second chance at life.

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You could be someone's hero - someone you don't know and may never meet, but to whom you can give the gift of life. How?  By donating bone marrow or peripheral blood stem cells.


Who Can be an Unrelated Bone Marrow or Stem Cell Donor?

In the United States, Be The Match® is the organization that matches patients who need a transplant with people who have volunteered to donate their bone marrow or stem cells to someone in need. 

Be The Match® focuses on recruiting people between the ages 18-40 because patients receiving cells from younger donors have a better long-term survival rate. Most of the time, physicians select donors between the ages of 18 and 32. Young adult donors have the healthiest, most robust blood stem cells, which produce the best results for patients

Click here for details about how to join the Be The Match® registry.

Before you can enroll as a donor in the Be The Match® registry, you need to meet certain health criteria. The medical guidelines for unrelated donors can be found on the Be The Match® website. 

If you live outside the U.S. go to Bone Marrow Donors Worldwide for information about the donor recruitment agency in your country.

Human Leukocyte Antigens (HLA)

To register as a potential donor, the Be The Match® Registry will need to know your HLA or human leukocyte antigen type.

  • Human leukocyte antigens are markers on your cells that help identify what belongs in your body.
  • Your HLA type needs to closely match the patient's in order for you to be a suitable donor.
  • You do not need to have the same blood type as the patient's in order to be a donor.

Your HLA type is determined by taking a swab of cheek cells from inside your mouth. The cells are sent to a special laboratory for analysis.

What Happens if I Match Someone Who Needs a Transplant?

Some people join the Be The Match® Registry and are called upon to donate within a matter of months. Others wait years, or are never called at all.  

If you are called upon to be a donor, you will receive extensive counseling about the donation procedure from a Be The Match® Registry representative. You will be asked to provide a blood sample for additional tests to confirm that you are a good match for the patient. You will have the opportunity to ask questions about how donating will impact your health and what type of time commitment is involved before making a final decision about whether or not to donate.

The Medical Procedure to Collect Bone Marrow or Stem Cells

The medical procedure you will undergo is described in the How Bone Marrow and Stem Cells are Collected section of our website. In most cases, the medical procedure will have a minimal, short-term impact on your health.

However, as with all medical procedures, there is a small chance that you may experience side effects that are more severe. Before you agree to be a donor, you will need a physical exam to determine whether donating is safe for you. Be sure to share with the doctor your complete medical history including illnesses and surgeries you have had in the past, even if you don't think they are important, as well as any current health conditions.

The patient to whom you are donating bone marrow or stem cells may live in any part of the world.

You will not have to travel to the patient's hospital. The bone marrow or peripheral blood stem cell collection will be done at a facility near you, and a courier from the Be The Match Registry® will deliver your cells to the patient's hospital.

Who Will Get My Bone Marrow or Stem Cells?

Many donors want information about the person to whom their cells will be given. Although you will not be told the patient's name, you will be given some information such as whether the person is a child or an adult, and the patient's gender and diagnosis. If you donate through Be The Match® you may be able to learn the patient's identity and how to contact him or her one year after transplant, provided the patient agrees to share this information.

Things to Consider Before Joining the Donor Registry

Before you join the registry, think carefully about whether this is a commitment you want to make. Although you can always change your mind after signing up, this can cause great distress for a patient's family, particularly if you are the only potential donor for the patient.

Agreeing to donate your marrow or stem cells can be a very emotional decision. You may be elated at the opportunity to give someone a second chance at life, and at the same time worry that your marrow or stem cells may not be "good enough" to make the transplant successful.

Many factors determine whether or not the transplant will be successful including the patient's age, diagnosis, stage of the disease and prior treatment. You are not responsible for the outcome of the transplant. You will have done your best by donating your cells, which will hopefully give the patient many more years of life.

Cord Blood Donation

If you will soon be having a baby, you may be able to donate your baby's umbilical cord blood to a patient who needs a transplant. Learn more about donating umbilical cord blood.

(To view this page in Spanish click here)

Next Page: Donating Umbilical Cord Blood

Updated August 2022