title: The differentiation of delayed hemolytic and delayed serologic transfusion reactions: incidence and predictors of hemolysis.
abstract: BACKGROUND
  After differentiation of the entities of clinically detectable delayed hemolytic (DHTR) and delayed serologic transfusion reactions (DSTR), previous investigators calculated a DHTR:DSTR incidence ratio of 18:72 from a retrospective review of patients with serologic evidence of DHTR or DSTR. There are no published data on factors that may influence the occurrence of DHTR versus DSTR in a given patient.
  
  
  METHODS
  Retrospective review was conducted of 292 patients at the Mayo Clinic who, between 1980 and 1992, received a clinical diagnosis of DHTR or DSTR concurrently with a serologic diagnosis. Red cell alloantibody specificity, the activity of the patient's reticuloendothelial system, and concurrent immunosuppression were evaluated as potential predictors of the occurrence of DHTR versus DSTR in different patients.
  
  
  RESULTS
  The incidence of DHTR or DSTR was 1 in 1899 allogeneic red cell units transfused, with a DHTR:DSTR ratio of 36:64. Alloantibody specificity was the only variable that affected the occurrence of DHTR versus DSTR at the clinical level, with the anti-Jka and anti-Fya specificities, as well as multiple coexisting specificities, significantly associated with detectable hemolysis (p < 0.05).
  
  
  CONCLUSIONS
  Clinically detectable DHTRs are found to occur more commonly than previously believed when the clinical and serologic diagnoses are made concurrently and appropriate work-ups for hemolysis are ordered. The association of certain alloantibody specificities with detectable DHTRs may have implications for clinical transfusion practice.
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota.
authors.forename: E C
authors.initials: EC
authors.lastname: Vamvakas
authors.forename: A A
authors.initials: AA
authors.lastname: Pineda
authors.forename: R
authors.initials: R
authors.lastname: Reisner
authors.forename: P J
authors.initials: PJ
authors.lastname: Santrach
authors.forename: S B
authors.initials: SB
authors.lastname: Moore
mesh_terms: D000328:Adult; D000368:Aged; D001789:Blood Group Antigens / Q000276:immunology; D001787:Blood Group Incompatibility / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006461:Hemolysis; D006801:Humans; D015994:Incidence; D007518:Isoantibodies / Q000097:blood; D008297:Male; D008875:Middle Aged; D065227:Transfusion Reaction
chemical_list: D001789:Blood Group Antigens; D007518:Isoantibodies