Summary: For men who have had a vasectomy, a post-vasectomy semen analysis (PVSA) approach that uses demonstration of absence of sperm on simple light microscopy in a single specimen of semen at 16 or 20 weeks post-vasectomy in order to determine “surgical success” may reduce the costs of PVSA by up to 40%. (In this study, further viability testing was recommended for any patient with persistent non-motile sperm at 20 weeks).

http://www.ncbi.nlm.nih.gov/m/pubmed/21388491/

Strength of Recommendation = B