Be The Match is one of the most recognized names in bone marrow and blood stem cell donation in the United States. It operates the world’s largest registry of potential donors, connecting people willing to donate with patients who need a transplant to survive blood cancers and other serious diseases. In early 2024, the organization officially rebranded under a single name, NMDP, though many people still know it by its previous names: Be The Match and the National Marrow Donor Program.
What the Registry Does
The core function of NMDP (formerly Be The Match) is maintaining a massive database of volunteer donors whose tissue types have been recorded. When a patient with leukemia, lymphoma, sickle cell disease, or another condition needs a transplant, their doctor searches this registry for someone whose tissue type closely matches. The U.S. registry currently contains more than 9.4 million potential adult donors, plus over 247,900 stored cord blood units. In fiscal year 2025, the program facilitated over 8,400 unrelated blood stem cell transplants, with more than 7,200 of those going to patients in the United States.
The matching process relies on specific proteins on the surface of your cells called human leukocyte antigens (HLA). These proteins are inherited, which is why your best chance of a match is usually someone from a similar ethnic background. That’s also where a significant gap exists: white patients have a 79% chance of finding a match on the registry, while Hispanic and Latino patients have a 48% chance, Asian and Pacific Islander patients have a 47% chance, and Black or African American patients have just a 29% chance. The more diverse the registry becomes, the better the odds get for everyone.
How to Join
Joining the registry is free and takes a few minutes. You can sign up online or at an in-person donor drive. The process involves filling out a health questionnaire, providing your contact information, signing an agreement, and swabbing the inside of your cheek. That cheek swab is what gets your tissue type recorded in the database. You’ll receive a kit in the mail if you register online.
The organization actively recruits people between the ages of 18 and 35. That’s not an arbitrary cutoff. Medical research consistently shows younger donors produce better outcomes for patients, so transplant doctors prefer donors in that age range. You need to be in good health and willing to donate to any patient in need.
What Happens If You’re Called as a Match
Most people who join the registry are never contacted. But if you do come up as a potential match, the process unfolds in stages over weeks or months. First, you’ll be asked about your current health and whether you’re still willing to donate. You may need to provide another cheek swab or blood sample so the patient’s doctor can get more detailed tissue typing information. This review can take up to 60 days.
If you’re confirmed as the best match, you’ll go through a full physical exam and blood work to make sure donation is safe for both you and the patient. From there, the timeline depends on which type of donation the patient’s doctor requests.
Two Types of Donation
The patient’s doctor decides which method is best. The two options are peripheral blood stem cell (PBSC) donation and surgical bone marrow donation.
PBSC donation is the more common method. For five days before donation day, you receive daily injections of a medication that pushes blood-forming stem cells from your bone marrow into your bloodstream. The first dose is typically given in a clinical setting, but the next three can be administered at your home, workplace, or a nearby clinic. On donation day, you get a final injection and then sit connected to a machine that draws your blood, filters out the stem cells, and returns the rest. This takes 4 to 8 hours for 98% of donors. The remaining 2% need a second session the following day.
Surgical bone marrow donation involves collecting liquid marrow directly from the back of your pelvic bone using a needle while you’re under general anesthesia. It’s an outpatient procedure, meaning you go home the same day or the next.
Recovery After Donation
Recovery depends on which method you undergo. After surgical marrow donation, you’ll likely feel pain at the collection site, especially when bending or walking. That pain tends to ease after the first few days. Most donors take several days off work to rest and gradually resume normal activities. Your bone marrow replenishes itself within a few weeks, and the total recovery period typically runs 2 to 6 weeks. Less common side effects include infection at the collection site, headaches, dizziness, and pain shooting down the leg.
PBSC donors commonly experience bone or muscle aches during the five days of injections, since the medication stimulates extra cell production inside the bones. These symptoms generally resolve within a few days after donation.
Costs to the Donor
Donating costs you nothing out of pocket. NMDP covers all medical expenses related to the donation, including lab tests and physical exams. You receive a special donor identification card to present at appointments so bills go directly to the organization, not to your personal insurance. If any donation-related medical bill accidentally reaches you, you’re told not to pay it yourself but to forward it to your assigned coordinator for resolution.
Travel is also covered. Airfare for you and a companion is arranged by your coordinator, and hotels are booked and paid for by your donor center. NMDP can also reimburse childcare expenses and lost wages within its guidelines. On top of that, if you experience any medical complications directly related to donation, expense coverage extends up to $1,000,000 for reasonable and customary medical charges within 260 weeks of the injury.
You aren’t financially compensated for donating. The organization frames it as a volunteer act, though the financial barriers to participating are deliberately removed.