Improved diagnosis of tuberculosis in lymph node cytology by bleach method for detection of acid fast bacilli in comparison to conventional ziehl neelsen staining method

Abstract

Background: Extra pulmonary tuberculosis (TB) is prevalent in developing countries and its diagnosis is often delayed, thus increasing the morbidity and mortality. Bleach method is cost effective, sensitive and safe method for demonstration of Acid fast bacilli (AFB) and is very valuable in diagnosing a case of tuberculous lymphadenitis. This simple procedure would benefit the patients to receive an early and specific treatment. Aims & Objective: The aim of our study was early diagnosis of tuberculosis in lymph node Fine needle aspiration cytology (FNAC) by bleach method for detection of AFB in comparison to conventional Ziehl–Neelsen (ZN) method. Material and Methods: Total 115 cases clinically suspected as tuberculous lymphadenitis in one year duration were included in study. All the aspirates by FNAC were processed for routine cytology, ZN staining and bleach method. The significance of the bleach method over the ZN method was analyzed using the χ2 (chi-square) test. Results: Among the 115 aspirates, 59.13% (68/115) were indicative of TB on cytology, 27.83% (32/115) were positive for AFB on conventional ZN method and the smear positivity increased to 61.74% (71/115) on bleach method. Conclusion: The implementation of the bleach method clearly improves microscopic detection of AFB over ZN method. The bleach method can be easily performed and reduce chances of laboratory acquired infections.