Most rapid diagnosis of pulmonary TB can be done by ?

Ans. is 'b' i.e., Sputum microscopy Sputum smear microscopy is the quickest and easiest procedure. But it lacks both sensitivity and specificity. Sputum culture is sensitive and most specific. But it takes 2-8 weeks for culture on routine L.J. media (solid medium). M tuberculosis produces visible colonies on solid media (L.J. media) in 4-8 weeks. Studies have shown that the rate of Isolation of positive cultures was significantly faster with the Bactec method with 87% of the positives being obtained at 7 days and 96% by 14 days. Gene XPe should be used as the initial diagnostic test in individuals suspected of having MDR-TB or HIV-associated TB (strong recommendation)," and "Xpe may be used as a follow-on test to microscopy where MDR and/or HIV are of lesser concern, especially in smear-negative specimens (conditional recommendation). The GeneXpe MTB/RIF assay is a novel integrated diagnostic device for the diagnosis of tuberculosis and rapid detection of RIF resistance in clinical specimens.