We compared the manual Polybrene technique to three standard methods (albumin/Coombs, LISS/Coombs, and enzyme/papain) on 113 red cell antibodies. Polybrene identified 8 antibodies of the Rhesus system missed by standard methods, whereas 3 antibodies could only be detected by the standard techniques. Four antibodies were identified only in saline solution at room temperature; 6 were found by use of Polybrene exclusively in the additional Coombs phase. In addition, 61 antibodies were tested by 4 different LISS. No considerable differences in the quality of the various LISS were seen. The manual Polybrene test appears to be suitable for crossmatching and rapid antibody identification in emergency situations.