Improved microscopical detection of acid-fast bacilli by the modified bleach method in lymphnode aspirates

Area of Science:

• Medical Microbiology
• Diagnostic Cytopathology
• Infectious Diseases

Background:

• Tuberculosis diagnosis often relies on smear microscopy.
• Fine needle aspiration cytology (FNAC) is used for lymph node biopsies.
• Acid-fast bacilli (AFB) detection in FNAC can be challenging.

Purpose of the Study:

• To enhance AFB detection in lymph node FNAC using the bleach method.
• To compare the bleach method with conventional Ziehl-Neelsen (ZN) staining and cytology.
• To evaluate the bleach method's effectiveness for tuberculosis diagnosis.

Main Methods:

• 99 patients with suspected lymph node tuberculosis underwent FNAC.
• Smears were analyzed using routine cytology, ZN staining, and the bleach method.
• Statistical analysis (chi-squared test) compared the methods.

Main Results:

• Out of 93 analyzed aspirates, AFB positivity was 33.33% (ZN), 41.94% (cytology), and 63.44% (bleach method).
• The bleach method demonstrated a higher detection rate for AFB compared to ZN and cytology.
• Malignancy and inadequate aspiration led to exclusion of 6 samples.

Conclusions:

• The bleach method is a simple, inexpensive, and effective technique for improving AFB smear microscopy.
• It reduces the risk of laboratory-acquired infections.
• Implementing the bleach method enhances microscopic detection and aids routine cytology for tuberculosis diagnosis.