An adult with cough and weight loss has two sputum samples submitted for mycobacterial evaluation. As per current Indian RNTCP/NTEP convention, what is the recommended initial test?

• A Ziehl-Neelsen smear followed by Löwenstein-Jensen culture only if smear positive
• B Tuberculin skin test to establish infection
• C Chest radiograph alone to confirm active disease
• D Xpert MTB/RIF (CBNAAT) directly on sputum ✓

Explanation

Indian programme policy uses Xpert MTB/RIF as the upfront diagnostic test for presumptive pulmonary tuberculosis because it detects M. tuberculosis DNA and rifampicin resistance within hours, including in smear-negative and HIV-infected patients. Smear-first algorithms miss paucibacillary disease, chest radiograph is nonspecific, and the tuberculin test measures latent infection rather than diagnosing active disease.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.