Under the National Tuberculosis Elimination Programme, a presumptive pulmonary TB patient undergoes Xpert MTB/RIF (CBNAAT) testing on a sputum sample. Besides confirming Mycobacterium tuberculosis, this test provides which additional key result?

• A Detection of resistance to rifampicin within about two hours ✓
• B Full drug susceptibility profile including isoniazid and pyrazinamide
• C Differentiation of M. tuberculosis complex from non-tuberculous mycobacteria by culture in 6 weeks
• D Quantitative measurement of bacillary load expressed as colony-forming units

Explanation

Xpert MTB/RIF is a real-time PCR assay that detects M. tuberculosis DNA and mutations in the rpoB gene conferring rifampicin resistance, giving a result in approximately two hours. It does not give susceptibility to isoniazid or pyrazinamide, which requires line probe assay or culture-based DST. This universal access to rifampicin-resistance detection is why NTEP recommends upfront molecular testing.

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.