A rare donor phenotype includes high-frequency-antigen-negative or multiple-common-antigen-negative or an IgA-deficient donor (concentration less than 0.05 mg / dL determined on two separate samples). Such donors need to be recognized, to overcome the most challenging situations of transfusion services, in providing antigen-negative compatible blood to patients with clinically significant antibodies against high prevalence antigens.
The requirement for rare blood donation to meet the transfusion needs of patients with unusual blood group antibodies was recognized in 1959, when the American Association of Blood Banks (AABB) set up a rare donor file. Subsequently with initiatives from the International Society Blood Transfusion (ISBT) and World Health Organization (WHO) the program was built up to generate data from various sources, predominantly UK, USA, and Japan. Later, in 1985, the ISBT rare donor working party was established. The working party developed guidelines for standardization of various activities, including testing, labeling, shipping of rare blood, updating the data base, and coordinating with the International Blood Group Reference Laboratory (IBGRL).
Presently there is a well-established American Rare Donor Program (ARDP) jointly managed by the American Red Cross and American Association of Blood Banks (AABB). The ARDP maintains a data base of donors and stock piles rare blood supplies. The European Data Base and Bank of frozen blood of rare groups, operating under the auspices of the European Directorate for Qualities of Medicines and Health Care, operates a similar program.
Identification of rare donors is a critical factor in establishing a rare donor registry. There are several ways by which a donor with rare phenotype can be identified. By performing mass screening of the donated red cell products, new donors with a rare phenotype can be identified. It involves antigen testing for one or two specific antigens in large batches. The use of automated methods like gel technology can be of real help in mass screening of the donated products. A patient with a rare group can be motivated to be an allogeneic donor once the patient recovers. Family members, especially siblings, may be tested to determine if they also have a rare phenotype.
Once identified such donors should be recruited in the rare donor panel. They should be informed about their rare phenotype and should be explained about the importance of their blood products to patients in need. The demographic details of such donors should be maintained and updated annually or semiannually. There should be adequate facility to freeze, store, and arrange for shipment of blood from such rare donors. Communication is another critical issue for the success of a rare donor program. If the requirement of a rare phenotype is not met from the national database, further search calls for an international collaboration to look for the desired phenotype.
In the Asian region, except for Japan, a rare donor registry program is yet to be established. The main limiting factors are limited availability of resources, lack of awareness among blood donors, as well as transfusion services and decentralized transfusion services in most of the nations. In the Indian subcontinent there is a well-established Immunohematology Reference Laboratory at the National Institute of Immunohematology, Mumbai, under the aegis of the Indian Council of Medical Research (ICMR), Government of India, where few rare donor phenotypes have been identified. However, in most of the blood banks, the antibodies of clinical significance are either not detected by the available serological technique, or if detected, are not identified.
The steps to set up a Rare Blood Donor Program in India should include:
- Creating awareness among the regular voluntary blood donors regarding the need to establish such a program
- Identifying and recruiting rare blood donors
- Retention of these rare blood donors
- Setting up national / regional reference centers to detect and identify the rare phenotypes
- Upgrading the transfusion services where these rare blood units can be stored in a frozen state for longer periods
- Effective communication between various blood banks/ blood transfusion services by linking through these national /regional reference centers
- Strengthening the training and education programs for technologists and clinicians, focusing on imparting knowledge regarding detection and identification of the alloantibodies and the importance of a rare donor program in preventing transfusion-related adverse events
In conclusion, the need for a rare phenotype blood may be faced by transfusion services at any point of time. To meet such a need at the right time, collaborative efforts of donors, doctors, paramedical staff, voluntary organizations and governmental commitment is required. It is time to take concerted efforts in this direction.