Comparison of a commercial hexadimethrine bromide method and low-ionic-strength solution for antibody detection with special reference to anti-K.

The sensitivities of manual low-ionic hexadimethrine bromide (Polybrene, LIP) and low-ionic Polybrene indirect antiglobulin tests (LIPAT) were compared with those of a manual low-ionic-strength indirect antiglobulin test (LISS) by using a commercial Polybrene kit. One hundred antibodies were coded, titrated, and tested in parallel. LIP did not detect 36 antibodies: 31 anti-K, two anti-E, two anti-Fya, and one anti-Jka. LIPAT did not detect seven anti-K, two anti-E, and two anti-Jka. The combination of LIP and LIPAT did not detect two anti-E that were reactive only in a two-stage enzyme test and seven anti-K that had titers of 2 or lower by LISS. LISS detected all antibodies except for the two enzyme-reactive anti-E. There were no significant differences in the titers of 63 percent of the antibodies studied. For 54 percent of the antibodies in the Kell system, LISS produced significantly higher titers; for 25 percent of antibodies in the Rh system, LIP did so. The poor sensitivity of the Polybrene kit for anti-K makes it unsuitable as a primary method for antibody screening.