Objective: To evaluate the predictive value of serum inhibin B (INH B) levels as an indicator of the presence of testicular spermatozoa in nonobstructive azoospermia.
Methods: Forty patients with nonobstructive azoospermia (NOA), 20 patients with obstructive azoospermia (OA), and 10 fertile volunteers were involved in this study. A chemoluminescence method was used to measure the levels of FSH; Inhibin B was analysed by using sandwich enzyme-linked immuno-sorbent assay.
Results: Patients with nonobstructive azoospermia has significantly higher levels of serum FSH [(21.34 +/- 12.15) IU/L] and significantly lower levels of inhibin B [(53.15 +/- 58.74) ng/L] than patients with obstructive azoospermia [FSH: (3.94 +/- 1.52) IU/L, INH B: (162.49 +/- 78.38) ng/L, P < 0.01] and fertile volunteers [FSH: (4.27 +/- 2.84) IU/L, INH B: (228.49 +/- 110.68) ng/L, P < 0.01]. Mean serum inhibin B were significantly higher in patients with nonobstructive azoospermia who had spermatozoa on TESE than in those in whom no spermatozoa was found on TESE [INHB: (90.31 +/- 72.18) ng/L vs (19.54 +/- 20.38) ng/L, r = 0.528, P < 0.01], but mean FSH levels did not have similar predictive power (P > 0.05).
Conclusion: Serum INH B level seems to be more accurate than serum FSH in the prediction of presence of testicular spermatozoa in patients with nonobstructive azoospermia. Serum inhibin B determination may be substitute of TESE as a diagnostic index.