Evaluation of the effects of four suspending media for test cells in antibody detection and identification is reported. The media under investigation are normal saline, low ionic strength salt solution, 22% bovine albumin and polymerized albumin. Hemagglutination at 37 C was enhanced in the test systems employing polymerized albumin. With shortened incubation times, the antiglobulin test was enhanced in tests against red blood cells suspended in the low ionic strength salt solution. When incubation times were extended to 30 minutes, all suspending media were apparently equally effective.