Relative ability of modified versions of the hamster oocyte penetration test, incorporating hyperosmotic medium or the ionophore A23187, to predict IVF outcome.

This study was designed to assess the relationship between IVF outcome and the results obtained with two modified versions of the zona-free hamster oocyte penetration test in which the spermatozoa were pre-incubated with either hyperosmotic medium or the divalent cation ionophore A23187. When the former system was used, a poor correlation with IVF outcome was observed. Samples screened prior to IVF exhibited a 60% false negative rate (failed penetration test, successful IVF), while for those assessed concurrently with IVF, the equivalent figure was 85.7%. Addition of A23187 optimized the penetration system giving higher levels of sperm--oocyte fusion and a more accurate prediction of the capacity of the spermatozoa to fertilize human ova in vitro. With this system the false negative rate was 4.3% for screened samples and 0% for those assessed simultaneously with IVF. These results suggest that the A23187-enhanced system may be of value as a screening criterion for IVF.