Auramine-O Staining vs Ziehl Neelsen Staining: Advantages and Disadvantages

Background: Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) is still a major public health concern around the world. Prompt detection of active tuberculosis cases helps in timely therapeutic intervention and reduces community transmission. Despite limited sensitivity, conventional microscopy is still used to diagnose pulmonary tuberculosis in high-burden nations such as India. This study, therefore, was aimed at assessing the diagnostic performance of microscopy by Ziehl Neelsen (ZN) and auramine (AO) staining in the diagnosis of pulmonary tuberculosis. Materials and methods: A prospective comparative study was done on the sputum samples of 2,395 adult patients from November 2018 to May 2020 suspected of having pulmonary tuberculosis visiting the Designated Microscopic Centre of SGT Medical College, Budhera, Gurugram. Each sample was subjected to ZN staining, and AO staining as per NTEP guidelines. Results: Out of the 2,395 samples studied, 161 (6.76%) and 224 (9.35%) were positive by ZN and AO staining methods respectively. Pauci-bacillary cases detected by AO were more than ZN staining. There were 63 more sputum samples detected by AO staining which were missed by ZN microscopy. Conclusion: When compared to conventional ZN staining, the auramine staining technique is more sensitive and takes less time to diagnose pulmonary tuberculosis