system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
In azoospermia, the diagnostic test which can distinguish between testicular failure and obstruction of Vas deferens is:
assistant
The correct answer is  As discussed in the preceding text: estimation of the levels of FSH can differentiate between pretesticular, testicular and posttesticular causes of male infertility.