Premium
The relative utility of the autologous control and the antiglobulin test phase of the crossmatch
Author(s) -
Perkins J.T.,
Arruza M.,
Fong K.,
Sosler S.D.,
Saporito C.
Publication year - 1990
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1046/j.1537-2995.1990.30690333479.x
Subject(s) - antibody , medicine , serology , sensitization , clinical significance , coombs test , immunology , isoantibodies
A retrospective study of pretransfusion testing records compared the utility of the antiglobulin test (AGT) phase of the crossmatch and the autologous control (auto‐control) for detecting clinically significant alloimmunization to red cells (RBCs). Of 110,780 consecutive crossmatches, 141 were positive after a negative antibody screening test; only 4 of these were due to alloantibodies of potential clinical significance, for a predictive value of a positive AGT crossmatch, after a negative antibody screen, of 2.8 percent (4/141). The frequency of potentially shortened RBC survival was 1 in 27,685 units crossmatched. During a similar period, 56,090 autocontrols were performed with the antibody screen. The autocontrol was positive on 902 samples in which the antibody screen was negative. Antibody identification performed in 684 cases generally yielded only cold or warm autoagglutinins. In 96 cases, some form of alloantibody was detected, but only 25 had potential clinical significance by our criteria. Eight of these alloantibodies had concurrently caused in vivo sensitization of RBCs and were classified as delayed hemolytic transfusion reactions. The predictive value of the autocontrol, calculated as the number of significant alloantibodies detected in autocontrol‐positive, antibody‐screen‐negative samples, was 3.6 percent (25/684). Inspection of these cases revealed 11 in which shortened RBC survival might have resulted if the serologic abnormality had not been detected. Thus, the autocontrol had a slightly greater yield of clinically significant findings than the AGT crossmatch. On the basis of these data, the AGT phase of the crossmatch was discontinued after a negative antibody screen with no record of alloimmunization and the autologous control was continued, but a decision was made to limit the indications for antibody identification when a positive autocontrol was the only serologic abnormality present in the initial pretransfusion tests.