In azoospermia, the diagnostic test which can distinguish between testicular failure and obstruction of Vas deferens is:: (A) Estimation of FSH level, (B) Estimation of testosterone level, (C) Karyotyping, (D) FNAC of testes
Answer is A. As discussed in the preceding text: estimation of the levels of FSH can differentiate between pretesticular, testicular and posttesticular causes of male infertility.