Errors inherent in the performance of a routine semen analysis.

A group of 26 medical laboratory technicians and pathologists performed a semen analysis on an aliquot of the same sample of semen. The mean sperm concentration obtained was 46.7 X 10(6)/ml +/- 40.1 (2 s.d.) with a range of values lying between 10 and 98 X 10(6)/ml and giving a coefficient of variation of 44.3%. Similar wide ranges were seen in the visual estimation of percentage motility and abnormal morphology. Results obtained from three technicians, all highly experienced in performing semen analyses, produced a mean sperm concentration of 66 X 10(6)/ml with a coefficient of variation of 37.8%. When the sperm concentration in semen was low, replicate analyses of four separate semen specimens produced coefficients of variation that were unacceptably high.