Relationship of acrosin activity to sperm function tests.

Acrosin activity of spermatozoa from infertile patients and fertile volunteers was measured. Acrosin activity of spermatozoa from asthenozoospermic patients and patients with unexplained infertility was lower than that from fertile volunteers. We utilize the zona-free hamster egg-sperm penetration test to select candidates for conventional in vitro fertilization among unexplained infertile patients. The zona-free hamster egg sperm penetration test, however, requires several hours and special equipment which are not used in the clinical setting. It is preferable that other sperm function tests or a combination of them can replace this test. Thus three distinct tests of sperm function, namely, acrosin activity, Penetrak test, hypo-osmotic swelling test, were compared with the hamster test, using spermatozoa from patients with unexplained infertility. A combination of the Penetrak test and measurement of acrosin activity could predict the results of the zona-free hamster egg sperm penetration test with 88.2% accuracy. Thus, the hamster test should be done when either Penetrak test or measurement of acrosin activity showed abnormal values.