A 30-year-old woman with primary infertility for 4 years has a hysterosalpingogram showing a 'pipe-stem' appearance of the tubes, bilateral tubal blockage at the cornua, and calcified lymph nodes on X-ray. Menstrual cycles are regular. Which investigation will provide the highest sensitivity for confirming genital tuberculosis as the underlying aetiology?
- A Endometrial biopsy for histopathology (granulomas with Langhans giant cells)
- B Serum interferon-gamma release assay (IGRA/QuantiFERON)
- C Mycobacterium tuberculosis PCR on endometrial aspirate (Gene Xpert MTB/RIF) ✓
- D Mantoux test > 15 mm in a BCG-unvaccinated woman
Explanation
For female genital tuberculosis (FGTB), culture of Mycobacterium tuberculosis from menstrual blood or endometrial tissue is the gold standard but has low sensitivity and takes 4–8 weeks. Gene Xpert MTB/RIF PCR on endometrial aspirate offers the best combination of sensitivity (~85–90%), specificity (~98%), and rapid results (2 hours) and detects rifampicin resistance simultaneously. It outperforms histopathology (which shows granulomas in only 50–60% of FGTB cases due to sampling issues). IGRA (QuantiFERON) indicates systemic TB exposure/infection but cannot diagnose genital TB specifically or distinguish active from latent disease. Mantoux is subject to false positives from BCG vaccination (India has universal BCG vaccination) and false negatives in immunocompromised states.
Reference: Shaw's Textbook of Gynaecology, 17th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.