A 28-year-old man with Crohn's disease on azathioprine has active ileocolonic disease (Harvey-Bradshaw Index 12) despite 3 months of optimised therapy. Anti-TNF therapy with adalimumab is initiated. Which monitoring parameter should be checked BEFORE starting adalimumab?
- A Thiopurine methyltransferase (TPMT) genotype
- B TPMT and full blood count only
- C Tuberculosis screening (IGRA/TST and chest X-ray) ✓
- D JAK1/2 kinase inhibition testing
Correct answer: C. Tuberculosis screening (IGRA/TST and chest X-ray)
Explanation
Prior to initiating anti-TNF therapy, tuberculosis screening is mandatory because TNF-alpha is critical for granuloma formation and maintenance; anti-TNF therapy reactivates latent TB. Screening includes IGRA (QuantiFERON-TB Gold) or tuberculin skin test plus chest X-ray. Latent TB must be treated (isoniazid 6–9 months) before anti-TNF initiation. TPMT testing is relevant before starting azathioprine/mercaptopurine, not anti-TNF agents.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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