Influence of system parameter settings on human sperm motility analysis using CellSoft.

The effect of changing CellSoft system parameter settings on measurements of motile sperm concentration and sperm movement characteristics (curvilinear and linear velocities, amplitude of lateral head displacement and beat/cross frequency) was investigated in semen. Specifically, the use of either four or 15 frames to distinguish motile from immotile cells was used in conjunction with a threshold curvilinear velocity of either 10 or 20 micron/s (recommended values: 4 and 10). In addition, a threshold for progressive motility based on linear velocity was also used by manual re-analysis of CellSoft Individual Cell Data printouts. Known reliable semen analysis methods or the analysis of manually reconstructed trajectories from videotape were used as standard methods for comparison. A curvilinear velocity threshold of 20 micron/s gave improved correspondence between CellSoft and standard methods for all characteristics evaluated. Whether a four or 15 frame setting was better varied with the measurement being made. However, using a linear velocity threshold to define the progressively motile sperm population provided the most acceptable values for sperm movement characteristics. Consequently, while substantial improvements in the measurements made by CellSoft can be obtained using different system parameters to those usually recommended, more reliable and certainly more useful information could probably be obtained if all analyses were performed on a defined population of progressively motile, and therefore potentially functional, spermatozoa.