Low hypo-osmotic swelling tests correlate with low percent motility and age of the male

To determine if sperm motility and hypo-osmotic swelling (HOS) test scores are associated. Furthermore the study would determine if the chance of having a subnormal HOS test increases as motility levels decrease. Finally the study would determine if age, motility, and HOS test scores are independent factors or if they interact. A retrospective analysis of males of all ages with a normal sperm concentration of > 20 x 10(6)/ml is presented. Males were evaluated separately according to age (< 40 vs > or = 40 years) for percent progressive motility and HOS test scores. The percent motility was assessed according to percentage in deciles. A significantly higher percentage of males with low motility have low (< 50%) HOS test scores irrespective of age. The odds ratio of males < 40 years having an abnormal HOS test score is 6.73 times higher and is 8.23 times higher for males > or = 40 years. As age increases, there is a significantly larger proportion of males with abnormal HOS test scores (6% to 13%). Factors that cause an abnormality in the functional integrity of the sperm membrane, as evidenced by a low HOS test score, can also have a negative effect on motility.