Figure 2.

Algorithm for the Work-Up of Low Volume Azoospermia. The physical examination is the key to diagnosis in the male with a low volume, acidic pH, azoospermic semen analysis. If the vasa deferentia are not palpable, Congenital Absence of the Vas Deferens is the diagnosis. If the vasa deferentia are palpable, most likely the diagnosis will be bilateral ejaculatory duct obstruction. The next step in diagnosis would be transrectal ultrasonography. CFTR, cystic fibrosis transmembrane conductance regulator.