ABSTRACT
A testis biopsy is performed to determine whether obstruction is present for an azoospermic man with palpable vasa deferentia. Testis biopsy can also provide some, but not absolute, diagnostic information for men with nonobstructive azoospermia (NOA). Only men with a serum follicle-stimulating hormone (FSH) level that is less than three times the upper limit of normal levels will have normal sperm production. Azoospermic men with small or soft testes are highly unlikely to have sperm production, but some of these men have limited foci of spermatogenesis that can provide sperm for assisted reproduction. In the authors’ experience, all men with congenital absence of the vas deferens, normal serum FSH levels, and normal volume testes (greater than 15 cc) had sperm production, obviating the need for diagnostic biopsy. Biopsy should be performed on both testes, since substantial differences in sperm production may be present without a palpable difference in the testes.
