Association between infertility following reversal of vasectomy and the presence of sperm agglutinating activity in semen.

A statistically significant association between infertility, following reversal of vasectomy, and the presence of sperm agglutinating activity in post-operative semen samples has been demonstrated in a retrospective study. Sperm agglutinating activity was measured using a microtitration assay, and the number of positive samples rose from 3/78 (4%) pre-operatively, to 34/134 (25%) post-operatively. High titres (greater than or equal to 1:32) of agglutinating activity were observed only when viable sperm were present in the ejaculate. Positive semen titres were obtained only when parallel serum samples were positive at titres of greater than or equal to 1:256. Conception only occurred in the partner of one man whose seminal plasma contained agglutinating activity, but 22/34 (65%) of the men whose semen lacked such activity were fertile.