ABSTRACT
AIM: The value of serum inhibin-B as a predictor of the presence of testicular spermatozoa is still controversial. The purpose of this study is to evaluate the predictive value of the seminal plasma inhibin-B level, which might more directly reflect the secretion by Sertoli cells, and to discriminate between successful and failed testicular sperm extraction (TESE) in non-obstructive azoospermia. METHODS: Sixty-two patients with non-obstructive azoospermia were examined at the Department of Obstetrics and Gynecology at Niigata University Hospital, Niigata, Japan. The level of inhibin-B was measured using a two-site enzyme-linked immunoassay. RESULTS: Testicular sperm were successfully retrieved in 17 of 62 patients (27.4%). The serum levels of follicle-stimulating hormone (FSH) were significantly lower and the serum and seminal inhibin-B concentrations were significantly higher in the successful TESE group compared with the failed TESE group. According to the receiver operating characteristics (ROC) curve analysis, the best discriminating seminal plasma inhibin-B level was 27.0 pg/mL (sensitivity 88.2%, specificity 93.3%). The best discriminating serum inhibin-B level was 34.0 pg/mL (sensitivity 70.6%, specificity 95.6%). The area under the ROC curve for seminal plasma inhibin-B was significantly larger than that for FSH and testicular volume. Using multivariate logistic regression analysis, only seminal plasma inhibin-B was an independent predictor of the presence of spermatozoa on TESE. CONCLUSION: Seminal plasma inhibin-B level is a useful predictor of the presence of testicular sperm in men with non-obstructive azoospermia.
