Correlation between intact sperm acrosome assessed using the Spermac stain and sperm fertilizing capacity.

Accurate determination of sperm acrosomal status is important in fertility studies. The objective was to correlate the percentage of intact acrosome assessed using the new Spermac stain with the capacity of sperm to fertilize oocytes. Sperm specimens were processed either by centrifuge wash, 48:95 Percoll gradient or test yolk buffer (TYB) wash, and tested using the zona-free hamster oocyte assay. The results indicated a correlation between the percentage of sperm with intact acrosome reaction and the percentage of sperm penetrating the oocytes in the TYB-washed group. The data suggest the usefulness of the Spermac stain for assessing the acrosomal status and in predicting the fertilizing capacity of the sperm.