In the context of ectopic pregnancy diagnosis, the transvaginal ultrasound discriminatory zone for serum β-hCG above which an intrauterine gestational sac should reliably be visible is:

• A 500 mIU/mL
• B 1000 mIU/mL
• C 1500 mIU/mL ✓
• D 3500 mIU/mL

Explanation

The discriminatory zone for transvaginal ultrasound is 1500 mIU/mL (Indian exam convention). Above this level, an intrauterine sac should be visible in a normal pregnancy; its absence raises suspicion for ectopic pregnancy. ACOG cites 3500 mIU/mL for transabdominal ultrasound, which is a common distractor. The 500 and 1000 values are too low and would not be discriminatory.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.