The manual polybrene test: a simple and rapid procedure for detection of red cell antibodies

A rapid manual Polybrene test for detection of red blood cell antibodies have been devised which uses standard laboratory equipment. Red blood cells are incubated with the test sera in a low ionic medium at room temperature for one minute. Polybrene, a quaternary ammonium polymer, is then introduced to cause nonspecific red blood cell aggregation. The test tubes are centrifuged, the cell free supernatant fluid decanted, and the Polybrene effect on the cells is neutralized by adding a dilute sodium citrate-glucose solution. The hemagglutination results are evaluated macroscopically and microscopically. The entire procedure is completed in less than three minutes. In the Rh system, the test is 10--160-fold more sensitive than the antiglobulin reaction. In other systems tested, except for the Kell, a high sensitivity is achieved. The sensitivity for the Kell system is markedly increased, however, by performing a supplementary antiglobulin reaction on the sensitized, Polybrene-treated, red blood cells. The antiglobulin reagent used for this purpose should lack anti-C4 and anti-C3 activities. Sensitivity for cold reactive antibodies is augmented by cooling the cells for 30 seconds before citrate-glucose reagent is added.