Safety and cost-containment data that advocate abbreviated pretransfusion testing.

Abbreviated pretransfusion testing, although permitted by American Association of Blood Banks Standards for unimmunized patients, is not widely practiced. Concerns remain about optimal antibody screening methods, antibodies missed by deleting the antiglobulin crossmatch, and cost-effectiveness. The authors prospectively tested 3,380 serum samples for blood type, antibody screen, and antiglobulin crossmatch. Antibody screens for 2,000 samples, performed with the use of a two-cell screen, were compared with 1,380 samples studied with a three-cell screen. Also, all 3,380 sera had major crossmatches performed carried through the antiglobulin phase. Two and three screening cells gave comparable results, with 5.45% of patients tested by two-cell and 5.22% by three-cell screens having a positive antibody screen. Of those with negative screens, 0.5% screened by two-cell screens and 0.8% by three-cell screens had a positive major crossmatch. Among these (negative antibody screen, positive crossmatch), only 0.03% (1 of 3.380) had a clinically significant alloantibody (anti-Kpa); 0.27% (9 of 3,380) had antiglobulin crossmatch positive with polyspecific antisera but negative with anti-IgG; and 0.12% (4 of 3,380) had positive crossmatch because of passive anti-A. By cost accounting of labor and reagents, 84 per unit would be saved using abbreviated versus complete pretransfusion testing. Blood banks now performing complete pretransfusion testing should reconsider abbreviated crossmatching for unimmunized patients as a safe, efficacious means of cost-containment.