title: The importance of antibodies against low-incidence RBC antigens in complete and abbreviated cross-matching.
abstract: BACKGROUND
  It is common practice to perform an antiglobulin cross-match only when unexpected RBC alloantibodies are present, to detect antibodies against additional RBC antigens. In this study, the incidence of unexpected antibodies to low-incidence antigens (Ab-LIA) over a period of 23 years was investigated.
  
  
  METHODS
  Records of RBC antibodies and the accompanying transfusion history from 1978 through 2000 was retrospectively examined. Complete cross-matches were performed for all RBC transfusions before 1991. As of 1991, the type-and-screen policy was applied. To study the incidence of anti-Wra, a prospective study was conducted on sera from 462 patients sent to the transfusion laboratory and 486 blood donors.
  
  
  RESULTS
  The records of 1795 patients containing 2257 RBC antibodies were examined. In 89 patients, a total of 94 Ab-LIAs was found. Anti-Wra was the most frequently encountered Ab-LIA. Thirty-nine patients had Ab-LIA in combination with other antibodies, 20 of which were autoantibodies. Eighty percent of these Ab-LIA were found at the first positive antibody screening test. Fifty-one solitary Ab-LIA were found in 50 patients, 37 during antibody screening tests, and 14 after positive complete cross-matches conducted before 1991. After an RBC antibody was detected, 664 patients received a total of 7792 RBC transfusions. Since the introduction of the type-and-screen policy, only one anti-Wra has been discovered during complete cross-matching. No transfusion reactions due to Ab-LIA were reported during the study period. In the prospective study, 12.3 percent of patients and 4.3 percent of blood donors had anti-Wra.
  
  
  CONCLUSIONS
  Although Ab-LIAs are found coincidentally in the sera of only 2 to 3 percent of patients with other RBC antibodies, they are formed often. Because we found no difference in serologic incompatibility, due to Ab-LIAs, between patients with and without other blood group antibodies, we conclude that blood can be transfused safely to patients without performing a complete cross-match.
authors.affiliation: Department of Hematology, Hospital Leyenburg, The Hague, The Netherlands. h.schonewille@leyenburg-ziekenhuis.nl
authors.forename: Henk
authors.initials: H
authors.lastname: Schonewille
authors.forename: Annette M
authors.initials: AM
authors.lastname: van Zijl
authors.forename: Pierre W
authors.initials: PW
authors.lastname: Wijermans
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000918:Antibody Specificity; D001782:Blood Donors; D001787:Blood Group Incompatibility / Q000175:diagnosis* / Q000276:immunology; D001788:Blood Grouping and Crossmatching / Q000379:methods*; D004912:Erythrocytes / Q000276:immunology*; D006801:Humans; D007518:Isoantibodies / Q000097:blood*; D007519:Isoantigens / Q000276:immunology; D008875:Middle Aged; D011446:Prospective Studies
chemical_list: D007518:Isoantibodies; D007519:Isoantigens