Can a Low Sperm Concentration without Assessing Motility Confirm Vasectomy Success? A Retrospective Descriptive Study

A fresh post-vasectomy semen analysis showing 100,000 nonmotile sperm/mL or less confirms sterility. Mailed sample or self-testing at home with SpermCheck® Vasectomy decreases the inconvenience of producing a fresh sample, but without assessing motility. We evaluated if there is a sperm concentration under which no motile sperm are observed that could fortify the use of these alternatives.

We conducted a study of post-vasectomy semen analyses performed at the andrology laboratory of the Quebec City university hospital, Canada. Sperm concentration and motility were assessed on fresh noncentrifuged 10 µL samples at 400× magnification. We calculated the proportion of post-vasectomy semen analysis showing motile sperm according to sperm concentration for all and first prescribed post-vasectomy semen analysis by the 5 physicians who performed the most vasectomies.

We identified 6,492 post-vasectomy semen analyses prescribed by 169 physicians. The 5 vasectomists prescribed 95.6% (6,204) of the post-vasectomy semen analyses; 96.1% (5,965) were first tests. We observed motility in all sperm concentration strata but it decreased with lower concentrations. At the first post-vasectomy semen analysis, among patients with less than 1 million, 250,000 and 100,000 sperm/mL, 0.5% (27/5,842) and 0.3% (19/5,760 and 17/5,725) had motility, respectively.

If the first post-vasectomy semen analysis on a mailed sample shows less than 1 million sperm/mL, we recommend requesting an additional mailed sample instead of a fresh sample. SpermCheck Vasectomy could falsely indicate a successful vasectomy in a very small proportion of cases. The optimal post-vasectomy semen analysis strategy must involve shared decision making, balancing the inconvenience of providing a fresh sample with the risk of a false-negative result.