AIMTo evaluate whether inhibin-B can predict the outcome of a microsurgical epidymal sperm aspiration (MESA) procedure in patients with suspected primary obstructive azoospermia (OA) and if inhibin-B can replace testicular biopsy in the diagnostic work-up of these patients.

METHODSInhibin-B levels and testicular biopsy scores were related to the outcome of MESA in 43 patients with suspected primary OA. MESA was considered to be successful when epididymal sperm could be identified during the procedure.

RESULTSSpermatozoa were present in the epididymal aspirate in 28 out of the 43 patients (65%). Inhibin-B values were not significantly different in patients with successful or unsuccessful MESA. The modified Johnsen score, however, was significantly lower in patients with unsuccessful MESA (P = 0.003). A rete testis obstruction or epididymal malfunctioning was found in 15% of patients with suspected primary OA, reflected by unsuccessful MESA despite normal inhibin-B levels and normal testicular histology.

CONCLUSIONInhibin-B cannot replace testicular biopsy as a diagnostic tool in the work-up of patients with suspected primary OA. Testicular biopsy is useful in identifying patients with spermatogenic arrest, who might have normal inhibin-B values.