Computer-Aided Sperm Analysis (CASA) of sperm motility and hyperactivation

Progressive motility is a vital functional characteristic of ejaculated human spermatozoa that governs their ability to penetrate into, and migrate through, both cervical mucus and the oocyte vestments, and ultimately fertilize the oocyte. A detailed protocol, based on the most common computer-aided sperm analysis (CASA) system with phase contrast microscope optics, is provided for performing reliable assessments of sperm movement pattern characteristics ("kinematics") in semen. The protocol can also be used with washed sperm suspensions where, in addition, the percentages of motile and progressively motile spermatozoa can also be derived. Using CASA technology it is also possible to identify biologically, and hence clinically, important subpopulations of spermatozoa (e.g., those in semen with good mucus-penetrating characteristics, or those showing hyperactivation when incubated under capacitating conditions) by applying multi-parametric definitions on a cell-by-cell basis.