The use of in vitro fertilization to evaluate putative tests of human sperm function.

Results of 106 in vitro fertilization procedures were used to evaluate the usefulness of tests of human sperm function for predicting fertilization rates. Sperm tests included concentration, motility, morphology, vitality (eosin Y exclusion), nuclear immaturity (aniline blue stain), and hypo-osmotic swelling. Only the number of sperm in the insemination medium, percentage normal morphology, and vitality were statistically significant in logistic regression models of fertilization rates. The other tests, such as the hypo-osmotic swelling test, did not give additional information about fertilization rates in this study. It is concluded that logistic regression analysis of factors affecting results of fertilization in vitro provides a powerful tool for evaluating some clinical tests of sperm function.