Coagulation and Transfusion Medicine

The routine pretransfusion red blood cell antibody detection test (PADT), performed at the authors' institution, consists of a threephase, saline-antiglobulin technique (immediate spin, 30-minute incubation at 37 °C, IgG indirect antihuman globulin test |IAT|), and each phase is examined for hemolysis and agglutination. To determine if it would be safe to omit reading the 37 °C phase of the PADT, a 6-year retrospective review of records (February 1986 to February 1992) was undertaken. Of approximately 280,000 sera tested for unexpected red cell alloantibodies, 1480 (.53%) were reactive at only 37 °C. Of 1480 sera, 1313 contained alloantibodies of no or questionable significance (eg, anti-Le", anti-Le\ anti-P,), 71 sera contained antibodies of undetermined specificity, and 10 sera were reactive because of rouleaux. Eighty-six serum samples from 53 different patients contained alloanti-