|One In A Million|
American Rare Donor Program
People come in all different shapes, sizes and blood types. The vast majority fall into one of the folllowing blood type categories: A, B, AB and O. But for a small percentage of the population, finding someone else with the same blood type can be as difficult as looking for a needle in a haystack. To make the matching process a little easier, the American Red Cross, in conjunction with the American Association of Blood Banks, maintains a rare donor database as part of the American Rare Donor Program (ARDP).
A person's blood type depends on the presence or absence of specific substances on the surface of red blood cells. Red blood cells are the portion of blood responsible for carrying oxygen throughout the body. These substances, called antigens, are made of mostly protein and carbohydrates and differ from person to person. Blood groups - the most familiar being A, B and O - are descriptions of certain antigens found on red cells.
However, there are more than 600 known antigens besides A and B that characterize the proteins found on a person's red cells. A combination of some of these less familiar but commonly occurring antigens are absent from the blood of an extremely small percentage of the population. There are also a few antigens that almost all people have on their red cells but that some lack. In either case - whether a person's blood has uncommon antigens or lacks common antigens - the person is usually categorized as having a rare blood type. Strictly speaking, a person's blood type is considered rare if only one other person in 1,000 lacks the same antigens or shares the same uncommon antigens. A person's blood type is considered very rare if only one person in 10,000 has or lacks similar antigens.
The human body naturally manufactures antibodies, even without ever having a transfusion, to the ABO antigens not present on its own red blood cells because it recognizes those antigens as foreign. For instance, people who are group A make anti-B. People who are group O make anti-A and anti-B, since they do not have either antigen on their red cells. When a patient requires a transfusion, to prevent a potentially life-threatening reaction, the blood he or she receives must not interact with these antibodies. For example, a patient who is group A has anti-B, so transfused blood must not be group B or group AB since these red cells carry the B antigen. When a person has a rare blood type and has formed the corresponding antibody, it becomes even more crucial to quickly find donor blood that lacks the same antigens. The goal of the ARDP is to maintain an up-to-date registry of all donors with these rare blood types so that any patient in need can quickly be transfused with blood that is safe for him or her.
Until just a few years ago, the Red Cross and the American Association of Blood Banks (AABB), a professional sociey for institutions and individuals involved in blood banking, maintained lists of rare donors separately. In 1998, the two programs pooled their resources and created the ARDP, a registry of more than 30,000 active donors. The ARDP is now the world's largest listing or rare blood donors.
Identifying Rare Donors
There are 80 ARDP member facilities, most of which are blood centers. All member facilities are certified by either the AABB or the Red Cross as immunohemtology reference laboratories. To be certified, each member lab must have the personnel and resources to perform complex antigen and antibody analyses.
Rare donors are usually discovered through blood screening efforts at one of the member labs or via family blood tests after a rare donor is identified. Most member institutions randomly screen donor blood as a way to identify potential rare blood donors, and in may cases, siblings of rare donors are recruited to have their blood screened and typed for unusual antigens or antibodies.
When a donor is identified as having a rare blood type, the referring member institution sends all of the donor's blood type and unique identifying information to ARDP headquarters in Philadelphia. Trained ARDP staff members then begin a password-secured process of data entry into the rare donor registry, including multiple verification steps along the way to ensure accuracy. Before adding the new donor to the registry list, his or her information is verified by the submitting ARDP facility.
Once the submitting facility verifies that the information is correct, a staff person contacts the donor and educates him or her about the program and the importance of becoming a regular donor. An average of 300 to 400 new rare blood donors are added to the computerized registry each month. To optimze donor retention and to keep the database as up-to-date as possible, the ARDP keeps close track of donor locations and requires the submitting facility to perform donor address confirmations twice yearly.
Processing Requests For Rare Blood
If a hospital patient needs rare blood, and its blood bank can't match the request, the hospital first requests help from its blood supplier. If the blood supplier does not have the matching blood but is an ARDP member, the ARDP may be contacted for assistance. Requests for rare blood can be placed at any hour of the day or night, seven days a week - ARDP staff are available on-site or via a remote connection at all times.
To fill a request for a patient needing rare blood, a trained ARDP staff person enters the patient's information and blood characteristics into a computerized database. The staff person then calls each ARDP member facility that comes up in the search results until the request can be filled. If none of the blood centers have the needed rare blood, a donor may be called in to meet the patient's need. In most cases, however, the ARDP member blood centers have frozen rare units available for immediate shipping. Generally, requests for rare blood are filled within 24 hours.
The ARDP receives an average of 40 to 50 rare blood requests each month, and over 1000 units are shipped annually. Most requests are for patients who lack an antigen present in 99 percent of the population, but there are many different kinds of rare blood types. In addition to domestic requests, the ARDP and its members provide rare blood products internationally on a regular basis. Since 1997, the program has coordinated shipments to Mexico, the Netherlands, Saudi Arabia, Sweden, Canada, Hong Kong, Japan and other countries, usually twice each month on average.