A novel laboratory procedure to validate American Urological Association guideline on vasectomy success and to diagnose obstructive azoospermia.

The objective was to develop a laboratory procedure to validate American Urological Association (AUA) Guideline on vasectomy success when nonmotile spermatozoa are found in the post-vasectomy ejaculate. The neutral α-glucosidase (NAG) an epididymal protein assay modified to determine the activity at 30 and 90 min of incubation from 24 pre- and 47 post-vasectomy ejaculates. The difference between the two points in the relative activity was calculated and if the difference was nonsignificant will confirm vasectomy success. The mean differences in the relative NAG activity were significantly different in pre- and post-vasectomy ejaculates, respectively. The mean differences in the relative NAG activity were similar in post-vasectomy ejaculates with and without nonmotile spermatozoa. No difference in relative NAG activity in post-vasectomy ejaculates between two time points of incubation may be a reliable method to confirm occlusion of the vas deferens. It also validates the recommendation by AUA Guideline on vasectomy success in the presence of few nonmotile spermatozoa.