Effect of swim-up, Percoll and Sephadex sperm separation methods on the hypo-osmotic swelling test

The separation of spermatozoa from the seminal plasma is required to prepare the spermatozoa for intrauterine insemination, in-vitro fertilization and sex selection. This study evaluated the effects of sperm preparation techniques on the functional integrity of the sperm membrane, as measured by the hypo-osmotic swelling test (HOS). Thirty-four semen specimens obtained from the male partner of infertile couples were evaluated. A semen analysis and HOS test were performed on each specimen. The remainder of the specimen was divided into three equal aliquots, the first prepared using Percoll, the second using a swim-up method and the third using a Sephadex column. After the preparation, a semen analysis and HOS test was performed on each aliquot. The mean and standard deviation for the HOS test was 72.9 +/- 8.5% initially, 71.2 +/- 13.1 after Percoll, 75.2 +/- 15.1 after swim-up and 62.4 +/- 14.5 after Sephadex. Analysis of variance showed that the mean HOS score was the same after Percoll and swim-up as it was initially but significantly lower after preparation with Sephadex. There was also a higher proportion of abnormal semen specimens (HOS less than 50%) after preparation with Sephadex than after the other preparation methods. We recommend the use of the HOS test as part of a screening panel for sperm separation.