title: Alloimmunization screening after transfusion of red blood cells in a prospective study.
abstract: BACKGROUND
  Several irregular red blood cell alloantibodies, produced by alloimmunization of antigens in transfusions or pregnancies, have clinical importance because they cause hemolysis in the fetus and newborn and in transfused patients.
  
  
  OBJECTIVE
  a prospective analysis of patients treated by the surgical and clinical emergency services of Hospital de Clínicas of the Universidade Federal do Triângulo Mineiro (HC/UFTM), Brazil was performed to correlate alloimmunization to clinical and epidemiological data.
  
  
  METHODS
  Blood samples of 143 patients with initial negative antibody screening were collected at intervals for up to 15 months after the transfusion of packed red blood cells. Samples were submitted to irregular antibody testing and, when positive, to the identification and serial titration of alloantibodies. The Fisher Exact test and Odds Ratio were employed to compare proportions.
  
  
  RESULTS
  Fifteen (10.49%) patients produced antibodies within six months of transfusion. However, for 60% of these individuals, the titers decreased and disappeared by 15 months after transfusion. Anti-K antibodies and alloantibodies against antigens of the Rh system were the most common; the highest titer was 1:32 (anti-K). There was an evident correlation with the number of transfusions.
  
  
  CONCLUSIONS
  Given the high incidence of clinically important red blood cell alloantibodies in patients transfused in surgical and clinical emergency services, we suggest that phenotyping and pre-transfusion compatibilization for C, c, E, e (Rh system) and K (Kell system) antigens should be extended to all patients with programmed surgeries or acute clinical events that do not need emergency transfusions.
authors.affiliation: Universidade Federal do Triângulo Mineiro - UFTM, Uberaba, MG, Brazil.
authors.forename: Vitor Mendonça
authors.initials: VM
authors.lastname: Alves
authors.forename: Paulo Roberto Juliano
authors.initials: PR
authors.lastname: Martins
authors.forename: Sheila
authors.initials: S
authors.lastname: Soares
authors.forename: Gislene
authors.initials: G
authors.lastname: Araújo
authors.forename: Luciana Cayres
authors.initials: LC
authors.lastname: Schmidt
authors.forename: Sidneia Sanches de Menezes
authors.initials: SS
authors.lastname: Costa
authors.forename: Dante Mário
authors.initials: DM
authors.lastname: Langhi
authors.forename: Helio
authors.initials: H
authors.lastname: Moraes-Souza