Background: Tubercular lymphadenitis (TBLN) is a significant diagnostic challenge in resource-limited settings due to its paucibacillary nature. While Ziehl-Neelsen (ZN) staining is widely accessible, its low sensitivity often leads to under diagnosis. This study evaluates the efficacy of the Modified Bleach concentration technique compared to conventional ZN staining, using CBNAAT as the reference standard. Materials and Methods: A hospital-based comparative cross-sectional study was conducted at the Chhattisgarh Institute of Medical Sciences among 75 patients with clinically suspicious tubercular lymphadenopathy. Fine-needle aspiration cytology (FNAC) was performed. Aspirates were processed via conventional ZN staining and the Modified Bleach method (using 5% NaOCl and centrifugation). CBNAAT/TruNAAT was used for confirmation. Statistical performance was evaluated based on sensitivity, specificity, and predictive values. Results: The disease predominantly affected young adults (21-30 years; 32%) and showed a female predominance (62.7%). Most nodes were single, unilateral (76%), and firm. Cytomorphological Pattern 6 (necrosis with inflammatory cells) was the most common finding (62.7%). The Modified Bleach technique demonstrated significantly higher AFB positivity (82.7%) compared to conventional ZN staining (42.7%). Notably, the bleach method detected AFB in 74.4% of ZN-negative cases (p = 0.029). Compared to CBNAAT, the Modified Bleach technique achieved 100% sensitivity and 100% NPV, whereas ZN staining showed poor sensitivity (52%) and NPV (37%). Conclusion: The Modified Bleach method is a highly sensitive, cost-effective, and practical tool that significantly improves the diagnostic yield of AFB in paucibacillary samples. It serves as a reliable alternative or adjunct to molecular tests in resource-constrained settings.

Tubercular Lymphadenitis, Modified Bleach Technique, FNAC, CBNAAT, Ziehl-Neelsen Staining