Significance of absent vas deferens at hernia repair in infants and children.

An absent vas deferens may be associated with unilateral renal agenesis or undiagnosed cystic fibrosis. Such patients should be further evaluated with a sweat chloride and intravenous pyelogram. The finding of absent vas deferens during exploration for an undescended testis does not provide absolute evidence for absence of the testis, since these structures have independent embryologic origins.