title: ABO antibody titers are not predictive of hemolytic reactions due to plasma-incompatible platelet transfusions.
abstract: BACKGROUND
  The overall risk of hemolytic transfusion reactions (HTRs) from plasma (minor)-incompatible platelet (PLT) transfusions and the role of a critical anti-A or anti-B titer in predicting and preventing these reactions has not been clearly established.
  
  
  METHODS
  We evaluated all apheresis PLT (AP) transfusions for 3 months. Using the gel titer method, we determined the anti-A and/or the anti-B immunoglobulin (Ig)G titer for all incompatible APs. Reported febrile transfusion reactions and HTRs were recorded; transfusions were not prospectively evaluated by the study team. A posttransfusion direct antiglobulin test (DAT) and eluate were performed after a reported febrile or hemolytic reaction for patients who received plasma-incompatible APs.
  
  
  RESULTS
  A total of 647 of 4288 AP transfusions (15.1%) were plasma incompatible. Group O APs (n = 278) had significantly higher anti-A and anti-B titers than group A or B APs (p < 0.0001). No group A or B APs had a titer of more than 128 (0/342). For group O APs, 73 had titers of 256 or greater (26.3%), and 27 had titers of 512 or greater (9.7%). No HTRs were reported to any plasma-incompatible AP transfusion during the study period. Two plasma-incompatible AP transfusions were associated with fever and chills and positive DATs, of which one had a positive eluate. The incidence of a DAT and eluate-positive febrile transfusion reaction in the plasma-incompatible AP population is 0.15% (95% confidence interval, 0.0%-0.86%).
  
  
  CONCLUSIONS
  A critical anti-A or -B titer is not sufficient to predict the risk of hemolysis in patients receiving plasma-incompatible APs, although underreporting of reactions to the blood bank may limit the generalizability of this study.
authors.affiliation: Department of Pathology, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Karafin
authors.forename: Lorraine
authors.initials: L
authors.lastname: Blagg
authors.forename: Aaron A R
authors.initials: AA
authors.lastname: Tobian
authors.forename: Karen E
authors.initials: KE
authors.lastname: King
authors.forename: Paul M
authors.initials: PM
authors.lastname: Ness
authors.forename: William J
authors.initials: WJ
authors.lastname: Savage
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology*; D000293:Adolescent; D000328:Adult; D000743:Anemia, Hemolytic / Q000097:blood / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D015142:Baltimore / Q000453:epidemiology; D001771:Blood Banks / Q000592:standards; D001787:Blood Group Incompatibility / Q000175:diagnosis / Q000276:immunology* / Q000517:prevention & control; D002648:Child; D002675:Child, Preschool; D003298:Coombs Test; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D015994:Incidence; D007223:Infant; D007518:Isoantibodies / Q000097:blood*; D008875:Middle Aged; D016134:Organizational Policy; D010949:Plasma / Q000276:immunology*; D017713:Platelet Transfusion / Q000009:adverse effects* / Q000379:methods; D010983:Plateletpheresis / Q000379:methods; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018570:Risk Assessment; D055815:Young Adult
chemical_list: D000017:ABO Blood-Group System; D007074:Immunoglobulin G; D007518:Isoantibodies