Does inhibin-B help us to confidently refuse diagnostic testicular biopsy in azoospermia?

Background: in the recent years, the use of laboratory blood factors such as fsh and inhibin-b for the assessment of spermatogenesis in different studies has increased; of course, the conflicting results have also been achieved.objective: to investigate if the measurement of inhibin-b can help surgeon to reduce unnecessary diagnostic testicular biopsies in males with azoospermia. materials and methods: this cross-sectional study was done during july 2006 to september 2007 on 41 patients with azoospermia. fsh and inhibin-b were measured and bilateral open testicular biopsy was performed for all patients. results: sperm was seen in 29% of biopsies that in 100% of these samples inhibin-b was more than 100 pg/ml and fsh was less than twice the normal (p=0.001). inhibin-b had significant correlation inversely with testicular fibrosis and sertoli cell only syndrome (p=0.043 and p=0.011, respectively) and directly with incomplete spermatocytic maturation arrest and obstructive azoospermia (p=0.027 and p=0.013, respectively). fsh was only correlated with obstructive azoospermia (p=0.001). conclusion: we suggest that if fsh is less than twice the normal, inhibin-b should be measured and if its level is less than 100 pg/ml, we can cancel about the half of unnecessary diagnostic testicular biopsies