Transfusing special populations: Autoantibodies:
As noted in Module 5, the serologic investigation of patients with both warm and cold-reactive autoantibodies can be extensive and time consuming. At the same time, these autoantibodies may render patients significantly anemic and accelerate the clearance of any transfused RBCs from circulation. As a result, it is often necessary to transfuse these patients before a full investigation can be completed.
To mitigate the risk of issuing units that are incompatible due to underlying alloantibodies, prophylactic matching for antigens that patients could develop antibodies to (according to their phenotype), is a commonly-employed strategy. Matching for the C, c, E, e and K antigens will prevent most alloantibodies, while more extensive matching (e.g., for the Fya, Fyb, Jka, Jkb, and S antigens) may render the risk of alloimmunization so low that repeat adsorption procedures may not be required for future transfusions. Thus, when determining the risk-benefit of transfusing a patient with an autoantibody before a complete investigation has been completed, it is important to review how well-matched their previous RBC transfusions have been. Policies may vary between individual blood banks
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