Improved motile sperm recovery by a hyperosmotic Percoll gradient

PURPOSE: Our purpose was to investigate whether a new, relatively hyperosmotic Percoll gradient, Enhance-S, can improve total motile sperm recovery rates compared with the commonly used Percoll gradient Perception. METHODS: Semen specimens from each of 17 donors were divided into two equal aliquots. One part was washed using Percoll Perception, while the other was prepared using Percoll Enhance-S. RESULTS: Compared to the unwashed specimen, sperm motion characteristics (motility and velocity) improved significantly after Percoll separation using either the Perception or the Enhance-S gradient. There was no difference in motility or velocity in spermatozoa recovered after wash with either of the two preparations. However, the total motile sperm recovery was significantly higher using the Percoll Enhance-S gradient than with the Percoll Perception gradient (P < 0.0024). CONCLUSION: The new Percoll Enhance-S gradient provides significantly more total motile sperm than the Percoll Perception gradient.