Microbiological diagnosis is the crux for the effective treatment of pulmonary TB (PTB). The search for rapid and efficient method has resulted in several modification of ZN stain. With this background this study was planned to compare the results of Revised National Tuberculosis Control Programme (RNTCP) advocated method of ZN stain with modified cold method using 7.5%phenol, 0.3% CF as recommended by WHO and IUATLD and 20% sulfuric acid as decolorizer. Objective of the research was to compare

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... the results of ZN stain (RNTCP) with the modified cold method, Compare the results of ZN stain (RNTCP) with Fluorescent microscopy. Material and methods: A prospective interventional study was carried using 266 sputum samples received at DMC. All the 266 samples were subjected to three methods-ZN stain modified cold stain and FM. They were compared for sensitivity and specificity in terms of qualitative results and grades of smear as recommended by RNTCP. Results: The smear positivity rate was 27.65%, 24.90% and 27.44% in Ziehl-Neelsen stain, modified cold stain and fluorescent microscopy respectively. Compared to ZN stain the proposed modified cold method has sensitivity of 90.41% and specificity of 100%. The concordance of qualitative result between ZN and modified cold method was 97.34%. Comparison of RNTCP grades of smear with ZN and modified cold stain has Kappa with Linear Weighting as 0.877 and Kappa with Quadratic Weighting as 0.877. Conclusion: Modified cold method cannot replace the ZN stain. However as it is economical and safe, can be adopted for training medical and paramedical students