OA3-AM24-SN-12 - Yields in Reiterated Homage to Landsteiner’s Law: Is Binding Blood Banks to ABO Reverse Typing Necessary in Donors with an Established Historical ABO Group? The ABO Reverse Typing (ABORT-Donor)
Background/Case Studies: Determining the ABO group for each blood donation requires performing a forward type (FT) and reverse type (RT), with expectations of Landsteiner’s Law being upheld. Discrepancies between FT and RT are infrequent, with a reported incidence in donors of ≤0.06%. The basis of ABO discrepancies is often in the RT, which requires additional resource-intensive testing, but rarely changes the final interpretation. We aimed to evaluate the impact of performing subsequent ABO reverse typing in donors whose ABO group had been conventionally examined at least once (both forward typing and reverse typing).
Study
Design/Methods: Electronic and paper donor testing records from 10/01/2021 to 12/31/2021 at one regional blood center were reviewed to identify donation events with ABO typing discrepancies. A systematic record review included identifying samples with no type determined (NTD) on initial testing (PK7300, Beckman Coulter Diagnostics, Brea, CA), NTD on a second automated platform (NEO, Werfen, Norcross, GA), and NTD in manual tube testing (Figure A); if NTD by all three methods, ABO discrepancy was confirmed.All events where an ABO discrepancy occurred were further characterized as a discrepancy in FT, RT, or both. Extended serologic testing to achieve a final ABO interpretation was captured, this ABO interpretation was compared to the historical type, when available, to determine concordance. The study data was collected and managed using an electronic data capture tool.
Results/Findings: In total, 61,430 typing events comprised of 51,417 donors were reviewed for ABO discrepancies. The incidence of ABO discrepancies was 0.099% (61/61,430). Of the typing events with historic ABO, 55/54,745 (0.1%) were identified with 3 due to FT-only, 49 due to RT-only, and 3 with both FT and RT discrepancies. In total 52/55 (94.5%) discrepancies were RT-based. After extended serologic testing, 3 persistently unresolved ABO typings were derived from the same donor who was known historically as group A, with a history of weak RT.There was no change to a donor's historical ABO from the 54,745 reverse typing events in the repeat donors over a period of 12 weeks. Due to weak/missing antigens in the forward type, two first-time donors were identified as ABO discrepant, most likely due to being a subgroup of A and a subgroup of B. Conclusions: The RT identified 2 likely subgroups in first-time donors, but in repeat donors, the performance of 57,431 RT (with extended serologic tests when applicable), yielded no events resulting in a change to the final ABO interpretation. The utility, economic impact, and environmental impact of repeat reverse typing in returning blood donors warrants further evaluation.
