A proposal for compatibility testing incorporating the manual hexadimethrine bromide (Polybrene) test.

In November 1984, the Standards Committee of the American Association of Blood Banks changed the requirements for pretransfusion testing by making the performance of an antiglobulin crossmatch optional when the antibody screening test is negative. The crossmatch would be necessary only to confirm ABO compatibility. Many will welcome this change; others will persist in their current methods. This article presents data supporting the use of the manual hexadimethrine bromide (Polybrene) test, a 1-minute room temperature procedure, as a crossmatch technique when the antibody screening test is negative. The manual Polybrene test (MPT) is an effective method for detecting ABO incompatibility. Forty-seven randomly selected serums gave expected results with A1, A2, and B red cells. Only 66 percent of 84 group B sera were serologically incompatible with A2B red cells by MPT, but the same results (69% positive) were observed using a 5-minute low-ionic-strength solution (LISS) room temperature technique. As only 37 percent of these crossmatches were incompatible using a LISS immediate spin (IS) method, the reliability of an IS method is questioned. An MPT crossmatch provides added security in that most unexpected blood group antibodies are demonstrable by this method. Of 106 serums tested which contained antibodies, 83 reacted. We believe that the MPT provides a rapid and sensitive test that, accompanied by a carefully performed antibody screening test, meets the requirements of Standards and will provide for safe red cell transfusion without the need for an antiglobulin crossmatch.