Incidence of serum agglutinating and immobilizing sperm antibodies in infertile couples

Blood specimens from 285 consecutive infertile couples were treated for sperm agglutination and for sperm immobilization by the tray slide agglutination test and a microimmobilization test. The immobilization test was positive only when the agglutination test was also positive. Sperm immobilizing activity in association with agglutinating activity was detected in the serum of 7.5% of the husbands and 1.4% of the wives. These sperm immobilizing activity figures may represent the actual incidence of antibodies in patients attending the author's service.