Prediction of in vitro fertilization outcome by sperm penetration assay with TEST-yolk buffer preincubation

Objective: To evaluate sperm penetration assay (SPA) value as a screening tool before in vitro fertilization (IVF). Design: Follow-up study comparing sperm variables and IVF outcome. Setting: Infertile couples in an academic research environment. Patients, Participants: Two hundred forty-one infertile couples scheduled for IVF. Interventions: Sperm penetrating assay with cold Tes-TRIS (TEST) Yolk buffer semen preincubation and IVF. Main Outcome Measures: Percent of egg penetration recoded into poor and good category (0% to 20%, 21% to 100%) and compared with fertilization, embryo transfer, and pregnancy rate (PR) in IVF, as well as sperm count motility and morphology. Results: Sperm penetrating assay predicted fertilization with a high negative (74%) and positive (82%) predictive rate and good specificity value (0.96). One of 31 patients in the poor SPA category (3%) fertilized >50% of eggs; no pregnancy occurred. In the good SPA category, 87 of 210 patients (41%) fertilized ≥50% of eggs with 34.3% PR. Sperm penetrating assay correlated better with fertilization rate than did sperm count and motility but not morphology. Conclusions: Sperm penetrating assay is a useful screening assay before IVF together with sperm morphology.