The Donation Process: Stages of Matching

A" Stem Cell" makes other blood cells

How a Match is Made
When you first register with the Be The Match Registry, an initial "tissue type" is performed on your cheek cells. This identifies your "tissue type" that is needed to be a stem cell match. This tissue type is then entered into the National Marrow Donor Program Registry where it is compared to the tissue typing of each patient searching for a donor. Stem Cells are normally produced in the bone marrow. They are responsible for forming the white blood cells, red blood cells and platelets in our body. These are the cells that are transplanted into patients in a marrow or peripheral blood stem cell transplant.

Early Matching
When someone in the registry is identified as a possible or preliminary match, the Donor Center contacts the potential donor to tell them they are a possible match, answers any questions they may have, and makes sure they are still interested in being on the Registry. The donor may be asked for another cheek swab if they registered many years ago and do not have a complete tissue type available or if their typing needs to be repeated with a higher level of testing. The potential donor will also be asked to complete a health history questionnaire to assess their current overall health. (see medical guidelines)

Confirmatory Typing
If the potential donor has a complete, high resolution typing available, the National Marrow Donor Program will request confirmatory typing on that donor. A potential donor identified at this stage usually has five or six markers matching the patient needing a transplant. This means they are a very close match and could be a possible donor. They may be one of only a few donors matching this patient, or one of several. The Donor Center search coordinator contacts the donor to discuss what it means to be a match, answer any questions the donor might have, make sure the donor is still in good medical condition and eligible to be a donor and schedules additional blood testing. Several tubes of blood are drawn from the potential donor and sent to the transplant center to be tested in conjunction with the patient's blood. Results of the blood tests usually take about six weeks, but can take several months.

Workup
This is the final stage of the matching process that occurs after a donor has completed the confirmatory typing process. A donor "at workup" has been identified as a match! The Donor Center contacts the potential donor to schedule an information session with the donor to thoroughly explain the procedure and answer all of the donor's questions. If the donor wished to proceed to donation, a complete physical exam is performed on the donor.

The transplant center (where the patient is located) will request that a donor consider one of two types of stem cell collections: marrow collection or peripheral blood stem cell (PBSC) donation.

• Marrow Collection: For marrow collection, the donor is scheduled for day surgery for the collection. This is to enable the physician to give the donor general anesthesia so the collection will not be painful for the donor. The marrow is collected through a needle placed into the iliac crest of the pelvic bone. Although the procedure is not painful, most donors do experience some soreness in the hip for several days following the procedure.

• PBSC Collection: For a peripheral blood stem cell (PBSC) collection, the donor is given an injection of a protein called filgrastim each day for five days. This increases the number of stem cells released from the bone marrow into the blood stream. On the fifth and sixth day, the donor's stem cells are collected by a procedure called apheresis. This is the same procedure used to collect platelets from a platelet donor. During apheresis, the donor's blood is removed through a sterile tube and passes through an apheresis machine that separates out the stem cells. Remaining blood, minus the stem cells, is returned to the donor in another sterile tube placed into the other arm.

If the potential donor decides to continue, he or she is scheduled for a physical examination to make sure he or she is in good health and that the donation procedure will not be dangerous to him or her in any way. The donor is then asked to sign an "intent to donate," the patient is told they have a matched marrow donor, and the target date for a transplant is set.

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