Can serum Inhibin B and FSH levels, testicular histology and volume predict the outcome of testicular sperm extraction in patients with non-obstructive azoospermia?

In our study, we evaluated the diagnostic accuracy of serum follicle stimulating hormone (FSH), Inhibin B, testicular volumes and distribution of testicular sperm extraction (TESE) outcome according to the histological diagnosis in men with non-obstructive azoospermia. Between February 2001 and April 2002, 66 men presenting with infertility of at least 1 year were found to have non-obstructive azoospermia. Serum FSH and Inhibin B levels, testicular volumes and pathological analysis were reviewed retrospectively using medical records of these patients. Of 66 patients, 52 were enrolled into the study and sperm extraction was successful in 31 of 52 patients (59.6%). There was no statistically significant difference between the patients who had successful and unsuccessful TESE in terms of mean serum Inhibin B, FSH levels and testicular volumes (P>0.05). The area under ROC analysis for serum Inhibin, serum FSH and testicular volume was 0.557, 0.523 and 0.479, respectively. For Inhibin B, the best cut-off value for discriminating between successful and failed TESE at 90% sensitivity was 6.25 with a very low level of specificity (14%) and diagnostic accuracy that was 53.8. Besides the controversies about the direct marker role of serum Inhibin B in determination of spermatogenesis, it does not seem to give a clue about the prediction of sperm presence before TESE. Because of the conflicting results in the literature, the potential role of serum Inhibin B as a marker for prediction of sperm presence in testis is yet to be determined.