EFFECT OF SPERM PREPARATION WITH TEST YOLK BUFFER ON SPERM-BINDING CAPACITY UNDER HEMIZONA ASSAY CONDITIONS

The study was conducted to evaluate the diverse effect and clinical si gnificance of TEST yolk buffer treatment on sperm samples of 128 infer tile men. Sperm samples were incubated with TEST yolk buffer and contr ol medium (Ham's F-10) at room temperature for 2 h. The hemizona indic es (mean +/- SE) of the TEST yolk buffer and medium-treated sperm samp les were 29+/-2.3% and 22+/-1.6%, respectively. Inspection of the indi vidual response of each sperm sample to TEST yolk buffer revealed that 63 samples (49%) improved (double the interassay variation=28%) their binding to zona pellucida, 36 (28%) remained unchanged, whereas the b inding capacity of 29 samples (23%) decreased. Furthermore, TEST yolk buffer treatment of 24 samples (19%) resulted in an increased binding beyond the hemizona index threshold set up at 23%. This level was prev iously shown to be the cut-off point between fertile and infertile spe rm samples. It was concluded that when applied to an unselected group of infertile men, TEST yolk buffer significantly increased sperm bindi ng capacity to the zona pellucida. However, only 19% of the sperm samp les showed improvement with clinical significance. The other sperm sam ples may have improved, remained unchanged or even deteriorated indepe ndently on basic sperm variables. Thus, the effect of TEST yolk buffer treatment on sperm binding should be tested prior to its clinical use to avoid possible damage to certain sperm samples.