A couple complains of primary infertility in spite of staying together for 4 years and having unprotected intercourse, all tests in a wife are normal. Semen analysis shows a volume of 0.8 ml/ sperm count is 0, fructose is absent what is done next?
Testicular FNAC
Ultrasound for obstruction
Local palpation of vas
Karyotyping
This is probably a case of obstructive azoospermia.
In this condition we need to know the site and nature of blockage. 
Among the given options ultrasound is the best. 
Vasogram can also be done.