Medical Director American Red Cross Philadelphia, Pennsylvania, United States
Background/Case Studies: The American Rare Donor Program (ARDP) supplies rare blood products to alloimmunized patients. Though most rare blood requests are for RBC units lacking blood group antigens, the ARDP also supplies IgA-deficient (IgAd) blood products, primarily plasma and platelets. Patients with absolute IgA deficiency (IgA level < 0.05 mg/dL) and anti-IgA may have the potential to experience anaphylactic transfusion reactions with IgA-containing blood products. The ARDP uses an evidence-based algorithm that includes laboratory testing and a history of anaphylaxis to determine if IgAd products are warranted (see Figure 1). This study aimed to analyze the requests for IgAd blood products received by the ARDP during a 5-year period.
Study
Design/Methods: The ARDP database was queried for all IgAd product requests received between 2018 to 2022. The ARDP algorithm as seen in Figure 1, was applied to each request to determine if the requests were valid. The requests were further analyzed by patient history of anaphylaxis and laboratory testing for IgA levels (routine and sensitive) and anti-IgA.
Results/Findings: Between 2018 and 2022, 79 requests for IgAd products were received for 64 patients. Collectively among the requests, 248 units of plasma, 34 platelets, and 7 RBCs were requested. Forty-six (58%) requests were made as emergent, defined as needed within 4 days, while 33 (42%) were non-emergent or not specified. Of the emergent requests, 28 (61%) met the guidelines to receive IgAd products. Eighteen (39%) requests did not qualify for IgAd products including 4 patients with past reaction(s) with no testing performed, and 6 requests for 5 patients with no history of past reaction(s) nor testing provided. Of the non-emergent or not specified requests, 14 (42%) were valid requests, 6 (18%) did not qualify for release of IgAd products, and 13 (39%) required additional lab testing. Of the 64 patients, 27 (42%) patients required additional testing, 13 (20%) were not eligible for IgAd products, and 24 (38%) were IgAd with anti-IgA present. Of the patients with anti-IgA present, 5 were reported to have a history of anaphylaxis to IgA-containing products, 1 did not have past reaction(s), while no history was provided for 18 patients. Conclusions: Though requests for IgAd products represent only 1-2% of rare blood requests received by the ARDP, they are challenging to manage, due to a lack of knowledge about the condition, appropriate testing, and alternatives such as washed cellular products. More education and access to testing are needed to assure that patients are evaluated for the appropriateness of rare blood products and that alternatives such as washed RBCs and platelets are explored, when appropriate.
Importance of research: Patients with absolute IgA deficiency and anti-IgA are considered most at risk for anaphylaxis to IgA containing products. The American Rare Donor Program receives multiple requests per year in which IgA deficient blood products are ordered but not indicated. Education is needed to assure patients are evaluated and/or tested appropriately prior to requesting IgA deficient blood products .
