Which statement correctly differentiates obstructive azoospermia from non-obstructive azoospermia?

• A. Obstructive azoospermia results from a blockage with normal sperm production; non-obstructive from impaired production.
• B. Obstructive azoospermia results from impaired spermatogenesis; non-obstructive from a blockage.
• C. Both have elevated FSH levels equally.
• D. Both require antibiotics.

Answer: (A)

The idea being tested is where the problem lies in azoospermia: in obstructive azoospermia the testicles make sperm normally, but a blockage stops them from reaching the semen; in non-obstructive azoospermia the sperm production itself is impaired.

This is why the statement that obstructive azoospermia results from a blockage with normal sperm production, while non-obstructive azoospermia results from impaired production, is the best description. It captures the essential difference between a functional block in the ductal system versus a problem with the testicular production of sperm.

The other notions don’t fit as well. Saying obstructive azoospermia is due to impaired spermatogenesis (and non-obstructive to a blockage) reverses the true relationship. Elevation of FSH in both conditions isn’t accurate—NOA more often shows higher FSH due to reduced spermatogenesis, whereas OA typically does not. And antibiotics aren’t a standard remedy for azoospermia unless an infectious cause is present.