The effect of a two-hour, room temperature incubation of human spermatozoa in TEST-yolk buffer on the rate of fertilization in vitro.

PURPOSE: To reassess the use of TEST-yolk buffer (TYB) in an in vitro fertilization (IVF) program by comparing fertilization rates achieved in a glucose-free cleavage medium by the standard IVF preparation of sperm versus a 2-h, room temperature incubation of sperm in TYB. METHODS: Oocytes collected for IVF were randomly split into two groups and inseminated with either TYB-treated sperm or IVF-prepared sperm. SETTING: Stanford Reproductive Endocrinology and Infertility Center. PATIENTS: Fifty couples undergoing IVF with at least 10 mature oocytes. MAIN OUTCOME MEASURES: Fertilization rates in vitro. RESULTS: Fertilization rates were significantly higher (p = 0.015) with TYB treatment. The average 2PN fertilization rate was 49.6% (188/379) for the IVF group and 57.4% (221/385) in the IVF with TYB group. CONCLUSIONS: A 2-h, room temperature incubation of sperm in TYB produces significantly higher 2PN fertilization rates as compared to standard IVF preparation of sperm in a current generation cleavage medium.