The human sperm hypoosmotic swelling test: its practical application and suggestions for improvement.

Semen samples of 209 males of infertile couples were evaluated by the sperm hypoosmotic swelling (HS) test, the in vitro human sperm zona-free hamster ovum penetration assay (SPA), and by the three main parameters of the spermatogram (concentration, motility, and morphology). Whereas the HS test and SPA were poorly correlated with one another, the former showed a correlation with motility, particularly in oligo-, astheno-, and teratospermic semen samples. The simple and inexpensive HS test may prove a worthwhile tool in the diagnosis of male infertility.