Blood Type and Bone Marrow Donorship

I am A Rh positive or A+.

I stole this verbatum from http://www.livingdonorsonline.org/marrow/marrow4.htm

Becoming a Donor


Your ability to donate bone marrow or peripheral stem cells depends on whether:

Your blood type and tissue antigens are compatible with the recipient, and
You are healthy enough to withstand the donation process.

To assess your ability to donate, there are several tests you will undergo. The form and timing of the tests will be determined by the donor registry, but here are typical tests:

1. Your Age

The first screen is age; you must be at least 18 but not older than 60 (age 55 for some registries). That is, at the very least you must be an adult to donate. And, research has shown that donations from older adults are less effective, hence a maximum age.

2. Preliminary Blood and Tissue Compatibility

The first step is to determine your blood type and tissue type. Testing is initially done by the swap of your cheek then done by drawing a blood sample. If you are a donor volunteer, these tests are part of the registration process. You pay for the testing, which ranges from $45 to $90. The results are input into the marrow registry and used to make a preliminary match with compatible recipients.

Blood Type. The first test determines your blood type. There are four blood types designated by the presence or absence of two antigens—the A antigen and the B antigen. Blood type A means you have the A antigen. Type B means you have the B antigen. Type AB means you have both antigens. Type O means you have neither antigen.

You must have a blood type compatible with the recipient or you will not be able to donate. Here is who can donate to whom:

Type A can donate to types A and AB.
Type B can donate to types B and AB.
Type AB can donate to type AB.
Type O can donate to types A, B, AB, and O.

Tissue Type. The second test run on the blood sample identifies your human leukocyte antigens (HLA). There are many different kinds of antigens, but there are three categories assessed for marrow donation, designated HLA-A, HLA-B, and HLA-DRB1. You inherit one set of these three antigens from each parent giving you a total of six HLAs.

A similar test is run on a blood sample from the recipient, and the antigens are compared. You might hear of a "six-of-six" match (all donor and recipient antigens match), or a "half match" (three of the six antigens are the same), or a "zero match" (none of the antigens matches). In the case of bone marrow donation, tissue typing is critical, so a perfect "six-of-six" match is required.

3. Detailed Blood and Tissue Compatibility

Once a potential recipient has been matched on a preliminary basis, more detailed compatibility testing is done. Again, a blood sample is drawn from you and tested.

DNA Testing. One test that's done is DNA testing. This testing is similar to the HLA testing but is more detailed. It uses sophisticated laboratory tests to determine the DNA of your antigens and compares the DNA code to those of the recipient.

Crossmatching. Crossmatching is a further testing of antigen compatibility. In this test, white blood cells from you are mixed with blood from the recipient. If the white blood cells are attacked and die, then the crossmatch is "positive," which is a negative as far as your ability to donate. It means the recipient is "sensitized" to you—the recipient has antibodies to some of your antigens—so the recipient's immune system would turn on the donated marrow and destroy it. If the crossmatch is negative, you are compatible with the recipient.

Note: the blood and tissue typing is rigorous because compatibility between the donor and recipient is essential to a successful transplant. As a consequence, many potential donors are ruled out. The odds of two individuals matching range from 1 in 20,000 to 1 in 50,000 depending on such factors as ethnic background. This is the primary reason why unrelated donation is so important.

4. Your General Health

At some point in the screening process, you will have a complete physical exam. You will share your medical history and possibly have a series of tests, such as a chest x-ray, electrocardiogram, blood tests, urine tests, and so on. Female donor candidates may also undergo a gynecological exam and mammography. You will also undergo testing for infectious diseases, such as HIV, hepatitis B, hepatitis C, syphilis, and other diseases. The purpose of the exam is to ensure you don't have any health conditions that would make it difficult for you to endure the donation process or that could result in your infecting the recipient with disease.

5. Other Assessments

Depending on hospital guidelines and transplant team protocol, there may be other assessments, such as psychological and financial reviews:

Donor and collection centers routinely provide an educational session on marrow donation as part of the registration and donation process. During that session you will be counseled about such topics as your ability to remain anonymous (for nondirected donation), the screening requirements, the risks of donation, your rights to withdraw, the impact on potential recipients, insurance coverage, possible subsequent donations, and alternative collection methods. (The content listed here is based on guidelines suggested by the World Marrow Donor Association.) This is an opportunity to ask yourself questions. What are your motives? Is it important to you to know the recipient and for them to know you? Are you committed to donation or were you pressured?

This educational session is an opportunity to explore any concerns you have about donation. Often, the donor or collection center will arrange to give you an out without embarrassment if you decide donation isn't for you.

You may also be asked about financial considerations. The monetary demands of donation are modest by comparison to whole organ donation, but you still need to be aware of the potential financial consequences. Can you afford the cost of the preliminary blood test? Can you get off work for testing, surgery (or apheresis), and recovery? Medical expenses generally are covered by the medical insurance of the recipient. But lost wages are not. What kind of paid sick leave and vacation do you have from your employer? Do you have other financial resources available if you need them? Do you need help raising money?  There are many organizations out there that can help support you if financial resources are available.