Abstract:
Background & Objectives: The conventional Ziehl-Neelsen staining method for
acid-fast bacilli (AFB) plays a key role in the diagnosis of tuberculosis by direct
microscopy. Its major disadvantage is low sensitivity. The present study was
performed to emphasize the role of bleach concentration method over conventional
direct smear microscopy for detection of tubercle bacilli (AFB) in fine needle
aspiration material of lymph nodes.
Methods: Fine needle aspirations (FNA) were done in 109 patients with clinical
suspicion of tubercular lymphadenitis. Smears from the aspirates were processed for
routine cytology and the conventional Z-N method. The remaining material in the
needle hub and/or the syringe was used for the bleach method. The significance of the
bleach method over the conventional Z-N method and cytology was analyzed.
Results: Among the 109 aspirates 35.78% were positive for AFB on conventional Z
N method, 43.12% were indicative of TB on cytology and the smear positivity for
AFB increased to 62.38% on bleach method.
Interpretation and Conclusion: The bleach method is simple, inexpensive and limits
the risk of laboratory-acquired infections. The bleach method improves the
microscopic detection of AFB and can be a useful contribution to routine cytology.
