[Influence of the depth of the sperm counting chamber on sperm motility]

To investigate the influence of the depth of the sperm counting chamber on sperm motility.

We measured the depths of sperm counting chambers using the Filmetrics F20 Spectral Reflectance Thin-Film Measurement System. Then, according to the WHO5 manual, we analyzed 36 semen samples for the percentages of progressively motile sperm (PR) and non-progressively motile sperm (NP) and sperm motility (PR + NP) with the Ruiqi CFT-9201 computer-aided sperm analysis system, and compared the results of analysis.

The depths of the 4 sperm counting chambers were 9.8, 12.7, 15.7 and 19.9 microm, respectively, and the obtained PR were (44.00 +/- 11.63), (41.96 +/- 12.62), (40.86 +/- 11.71) and (37.78 +/- 11.38)%, NP (13.54 +/- 3.01), (14.13 +/- 2.94), (14.91 +/- 3.02) and (16.53 +/- 2.77)%, and sperm motility (57.53 +/- 11.06), (56.08 +/- 11.97), (55.78 +/- 11.55) and (54.31 +/- 12.11)% from the 4 chambers, respectively. The depth of the sperm counting chamber was correlated negatively with PR (r = -0.993, P < 0.05) and sperm motility (r = -0.978, P < 0.05), but positively with NP (r = 0.989, P < 0.05). There were statistically significant differences between the 9.8 microm and 19.9 microm deep chambers in PR and NP (P < 0.05) though not in sperm motility among the 4 chambers of different depths.

The impact of the depth of the sperm counting chamber on sperm motility should not be ignored, for the deviation of the results from the chambers of different depths may lead clinicians to incorrect diagnosis and consequently inappropriate therapeutic approaches. Different reference ranges of sperm motility need to be normalized in correspondence to the depths of sperm counting chambers.