Diagnostic value of the zona-free hamster oocyte penetration test and sperm movement characteristics in oligozoospermia.

A group of 27 oligozoospermic patients were followed up for 4.2 +/- 1.1 years in a prospective study designed to determine which aspects of semen quality are of value in the diagnosis of fertility. The semen analysis included the zona-free hamster oocyte penetration test, the assessment of sperm movement characteristics by time exposure photomicrography and a conventional semen profile. During the follow up period, 7 patients (25.9%) initiated a pregnancy. The identity of these fertile subjects could not have been ascertained by any single criterion of sperm movement or any feature of the conventional semen profile. The zona-free hamster egg penetration rates were also of little value in this respect since 4 of the 7 fertile patients scored 0% in this assay. Using a multivariate discriminant analysis, however, a combination of 7 criteria was identified, including hamster oocyte penetration and elements of both sperm movement and the semen profile, which could predict the fertility of these patients with 85.2% accuracy.