TITLE:
Evaluation of Increased Sensitivity of Morning Bleach Sample for Detection of Acid Fast Bacilli in Pulmonary Samples
AUTHORS:
Pranali Pingle, Pradeep Apte, Rakesh Trivedi
KEYWORDS:
Pulmonary Tuberculosis, M. tuberculosis, Bleach Method
JOURNAL NAME:
Journal of Tuberculosis Research,
Vol.2 No.3,
September
3,
2014
ABSTRACT: Around 85% of the cases of Tuberculosis (TB) are pulmonary in origin and the routine diagnosis usually depends on sputum microscopy. The conventional direct Ziehl-Nelson (ZN) staining technique has been found to have a low sensitivity. The main objective of the study was to verify whether the bleach concentration method increases the sensitivity of sputum smear microscopy for AFB or not and also to see whether the first single morning sample alone is sufficient and better than the three pooled samples after bleach concentration followed by ZN staining. A total of 365 samples were studied from 131 clinically suspected cases of pulmonary TB which included sputum (112), gastric aspirate (5), endotracheal tube washing (2), and bronchial lavage (12). All these samples were processed for conventional ZN staining and Bleach concentration method followed by ZN staining. An increase in positivity was observed in all the cases after using the bleach concentration method and the most significantly useful was that in the case of first morning sputum samples where it increased from 11.6% to 41.96%. Bleach concentration is a simple, cheap and easily available method and also very safe because it kills the Mycobacteria in the process. Its positivity rate is better as compared to direct conventional ZN staining.