Comparison of antibody titers in donor specimens and associated AS-1 leukoreduced donor units.

Background Donor units with unexpected antibodies to red blood cell ( RBC) antigens have transfusion restrictions and are often discarded by collection facilities. This study examined the antibody titer reduction in AS-1 leukoreduced RBC ( LR- RBC) units and potential acceptability of these units for unrestricted transfusions. Study Design and Methods Donor specimens and AS-1 LR- RBC segment samples from donors with positive antibody screens and group O donors were analyzed. Antibody identifications were performed, and titer results from the matched serum samples and segment supernatants were compared. Results During the 5-month study, 39 donor samples with positive antibody screens, five random group O donor samples, and the associated LR- RBC unit segments were assessed. The median donor sample and segment supernatant titers were 4 and 1, respectively. Alloantibodies were undetectable in 28% of the donor segment supernatants. The median anti- A and anti- B titers in the group O donor samples were 128 and were reduced to 32 in the donor segment supernatants. All ABO and other antibodies were diluted by the AS-1 to a titer of not more than 32. Conclusion Antibody titers in AS-1 LR- RBC units were significantly decreased compared to donor specimens and were lower than anti- A and - B titers in group O AS-1 LR- RBC units, which are frequently transfused to non-group O recipients. If a 'clinically significant' titer for donor alloantibodies was established, blood centers could determine eligibility of units for unrestricted transfusions. This would decrease unnecessary RBC wastage and increase units available for transfusion. [ABSTRACT FROM AUTHOR]