A 29-year-old man is evaluated for infertility. He has had type 1 diabetes mellitus since age 12. Semen analysis: volume 0.8 mL, pH 6.7, sperm concentration 2 million/mL, poor motility. Testicular volumes are normal bilaterally and the vasa are palpable. Which single test will CONFIRM the underlying diagnosis?

• A Serum FSH and LH measurement
• B Post-ejaculatory urinalysis for spermatozoa ✓
• C Scrotal ultrasonography
• D Testicular fine needle aspiration

Explanation

Diabetic autonomic neuropathy can cause failure of bladder neck closure at ejaculation, so semen passes retrogradely into the bladder. This produces classic findings of low semen volume, acidic pH (because alkaline seminal vesicle fluid is lost), and low sperm count despite normal testicular function. Demonstration of spermatozoa in the post-ejaculatory urine confirms retrograde ejaculation. Serum gonadotropins would be normal here and are used to distinguish spermatogenic failure, while ultrasound and aspiration address obstructive or testicular pathology that this presentation does not suggest.

Reference: Williams Gynecology, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.