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Anti‐A and anti‐B titers in pooled group O platelets are comparable to apheresis platelets
Author(s) -
Cooling Laura L.,
Downs Theresa A.,
Butch Suzanne H.,
Davenport Robertson D.
Publication year - 2008
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/j.1537-2995.2008.01814.x
Subject(s) - titer , apheresis , agglutination (biology) , group b , group a , platelet , medicine , chemistry , immunology , antibody
BACKGROUND: Although uncommon, acute hemolytic transfusion reactions (AHTRs) have been reported after transfusion of group O single‐donor apheresis platelets (SDPs) to group A, B, and AB recipients. Current methods for identifying “high‐titer” SDPs include tube and gel methods. The risk of a high‐titer unit is considered low with group O, poststorage, pooled platelet concentrates (PPLTs); however, data regarding anti‐A and anti‐B titers in PPLTs are lacking. STUDY DESIGN AND METHODS: Anti‐A and anti‐B titers were determined in 185 PPLTs by direct agglutination using manual gel and tube methods. PPLTs tested included 124 group O PPLTs, 25 group A PPLTs, 26 group B PPLTs, and 10 PPLTs containing a mix of either groups O plus A or groups O plus B (mixed PPLTs). The reciprocal of the highest dilution giving macroscopic agglutination was considered the agglutinin titer. RESULTS: Mean anti‐A and anti‐B titers in group O PPLTs were, respectively, 16 and 8 by tube and 64 and 32 by gel (p < 0.0001). Gel titers were one to two dilutions higher than tube and sensitive to reagent red cell lots. With the use of at least 64 as a critical titer, 60 percent of group O PPLTs tested by gel would be considered high‐titer. In mixed PPLTs, the addition of one non‐group O PLT significantly decreased or neutralized the corresponding anti‐A or anti‐B (p < 0.0001). CONCLUSION: Anti‐A and anti‐B titers in group O PPLTs are comparable to those reported in group O SDPs and significantly lower than titers reported in AHTR. A critical direct agglutinin titer of 64 for identifying high‐titer units by gel is too low and should be increased to 128 or higher.