Serum inhibin B determination is predictive of successful testicular sperm extraction in men with non-obstructive azoospermia.

Recent work indicates that serum inhibin B is a useful marker of spermatogenesis and inhibin B production sufficient to maintain detectable serum concentrations in adults depends on spermatogenic activity. The purpose of the present study was to investigate the usefulness of serum inhibin B measurement to predict the success of testicular sperm extraction (TESE) in 17 men with nonobstructive azoospermia to be treated by intracytoplasmic sperm injection (ICSI) (group 1). Two additional groups were used as positive controls; group 2 comprised 22 infertile men having obstructive azoospermia, and group 3, which included 29 semen donors having normal seminal parameters. Follicle stimulating hormone (FSH) was significantly higher (P < 0.01) and inhibin B significantly lower (P < 0.001), in group 1 as compared with groups 2 and 3. Serum inhibin B concentrations were significantly higher (P < 0.001) among successful TESE men as compared with those having failed TESE. In contrast, no differences were detected between these two groups with respect to serum FSH or testicular size. In addition, serum inhibin B but not FSH discriminated between successful and failed TESE in group 1 subjects as compared with control groups. According to the receiver operating characteristics curve analysis, the best inhibin B value for discriminating between successful and failed TESE was >40 pg/ml (sensitivity 90%, specificity 100%). It is concluded that inhibin B measurement is a useful non-invasive predictor of spermatogenesis and thus, all azoospermic males should have serum inhibin B concentrations determined in addition to FSH measurement and karyotyping prior to undergoing TESE.