Tests to measure the quality of spermatozoa at spermiation.

This commentary is to critique the revised World Health Organization (WHO) semen analysis manual as it pertains to characteristics of a spermatozoon at spermiation. The aims of the revised WHO manual include improving the 'quality of semen analysis' without any restriction to clinical use. Furthermore, the manual states that semen analysis may be useful for (a) 'investigating male fertility status' and (b) 'monitoring spermatogenesis during and following male fertility regulation.' However, if the analysis of ejaculated spermatozoa is intended for the purposes described in (b), then cells that are abnormal at spermiation must be identified. This paper takes the position that the manual does not identify methods to estimate the quality of spermatozoa at spermiation. Instead, it uses a 'gold standard' of sperm passing through the cervical mucus or arriving near the site of fertilization. Although this standard is appropriate for drawing conclusions regarding the probability that an individual could impregnate his partner, it is not appropriate for studying illness of the testes per se. Herein, the measures of sperm quality presented in the WHO manual are critiqued with respect to the detection of spermatozoa that were abnormal at spermiation vs. those that became abnormal subsequently. Quality assessments based on the percentage of motile or 'viable' spermatozoa are meaningless. Alternative quality attributes defining spermatozoa at spermiation are presented in this paper. In conclusion, assessment of spermatozoal quality at spermiation, on the basis of quality attributes of individual ejaculated spermatozoa, is best achieved through application of (a) a new paradigm for the morphological evaluation of sperm quality and (b) modern analytical techniques to evaluate, in an adequate sample, several appropriate independent attributes in each spermatozoon in order to more accurately identify the proportion of abnormal spermatozoa.