Sperm function assays and their predictive value for fertilization outcome in IVF therapy: a meta-analysis.

The prevalence of male infertility and the availability of new, highly successful therapeutic options make the testing of sperm functional competence mandatory. An objective, outcome-based examination of the validity of the currently available assays was performed based upon the results obtained from 2906 subjects evaluated in 34 prospectively designed, controlled studies. The aim was carried out through a meta-analytical approach that examined the predictive value of four categories of sperm functional assays: computer-aided sperm motion analysis (CASA); induced-acrosome reaction testing; sperm penetration assay (SPA); and sperm-zona pellucida binding assays for IVF outcome. Results demonstrated a high predictive power of the sperm-zona pellucida binding and the induced-acrosome reaction assays for fertilization outcome. On the other hand, the findings indicated a poor clinical value of the SPA as predictor of fertilization and a real need for standardization and further investigation of the potential clinical utility of CASA systems. This analysis points out to limitations of the current tests and the need for standardization of methodologies and provides objective evidence on which clinical management and future research can be based.