Rare blood types: How to find a transfusion match?
Case Study (based on true events, altered for patient’s privacy):
A 25 year old female patient visiting from out-of-state presents to the hospital in early labor; she is 39 weeks pregnant. She has a blood disorder which makes her chronically anemic, and her pregnancy has exacerbated her anemia. Her blood bank work-up detected an antibody against a high prevalence antigen which often makes compatible blood very hard to find. This antibody, anti-U alloantibody, is directed against an antigen that is present in 99.9% of the population (U=universal!). Her current hemoglobin is 5.6 gm/dL and she is in labor. What do we do?
What do we do when we cannot find blood for someone in need of urgent blood transfusion?
This can be (and often is) a very difficult situation for both the blood center and hospital. Our goal as a community blood center is to provide life-saving transfusion for patients in need. And our hospital partners depend on us for fulfilling this patient need.
Note: When in doubt, hospitals always have emergency release blood available. This blood may not be (and likely isn’t) crossmatch compatible for rare blood types, but it is always an option during emergencies.
Sometimes it’s important to look closer to home before we search for a rare blood unit. Can the patient donate blood for their own use (autologous donation) if they have an upcoming procedure that they need blood for? Do they have a family member with the same rare blood type? If so, can their family member donate a compatible rare blood unit?
How does Carter BloodCare locate rare blood?
First, we try to find compatible rare units in our own inventory or antigen-typed donor database. We keep rare units both in our liquid and in our frozen inventory just for situations like this. (We have over 500 frozen rare units!) If we don’t have access to the specific rare unit(s) needed & we can’t call a donor in to donate, then we can reach out to the American Rare Donor Program (ARDP), for which we are a member (since we are an AABB accredited Immunohematology Reference Laboratory (IRL)). We screen by serology & molecular methods thousands of donors per year for rare antigen types in accordance with AABB IRL standards and the ARDP’s membership criteria. This is to ensure a continual supply of rare blood for patients in need locally and nationally. The other members of ARDP also contribute to this national rare donor registry, and we, ultimately, all have access to a much larger network of rare blood donors. It’s really a smart way to combine resources for the benefit of patients!
At Carter BloodCare, we currently have 1,621 active rare donors in the ARDP database that will donate when their unique blood type is needed for a patient. RBC units from these donors (and other rare donors that we identify) can be frozen up to 10 years in our onsite rare RBC inventory. In addition to having frozen, rare RBC units available for our hospital partners, we also ship rare RBCs across the country when we have available units. In 2020, we shipped 35 units to other blood centers for patients in need of a rare blood transfusion.
How do you become an ARDP Member?
Your lab must be an AABB accredited Immunohematology Reference Laboratory (IRL), and it also must fulfill certain criteria to contribute to the rare donor registry. This may involve serologically and/or genotyping a certain amount of blood donors for high prevalence antigens, shipping a certain amount of rare units to other ARDP members, or fulfilling other requirement criteria.
What defines a rare blood type?
A rare blood type must fall into one of the following categories as defined by the ARDP:
Negative for a high prevalence antigen (<1/1,000)
Negative for multiple common antigens
IgA deficient
Case Conclusion: What happened to the patient who needed rare blood?
The pregnant patient in need of rare blood required 2 of our frozen rare units to be thawed for transfusion. As she was already in early labor, there was no time to search for a potentially compatible family member. She received the 2 transfusions in anticipation of her delivery as she was already significantly anemic. She delivered a healthy baby and required no additional blood. We were happy to be able to contribute to her care in such a meaningful way!
Special thanks to Sandy Wortman, MT (ASCP) SBBCM for her contribution to this entry.