Comparative evaluation of different staining techniques for diagnosis of pulmonary tuberculosis

Abstract

Introduction: We have various diagnosis methods for tuberculosis, however, sputum smear microscopy is the simplest, rapid and cheapest method. Aims and Objectives: The purpose of this study was to detect Mycobacterium tuberculosis (MTB) in clinically suspected cases of pulmonary tuberculosis by using staining methods. Methods: A prospective examination of samples were performed in the department of microbiology in Government Medical College, Amritsar. During this study, a total of 100 sputum samples from patients clinically suspected of pulmonary tuberculosis were collected in sterile leak-proof containers as per RNTCP guidelines. The collected samples were divided into the following three parts: initial part was processed before decontamination; Second part processed post-NALC-NaOH method and third post Bleach method and then subjected to ZN, Kinyoun and Fluorescent staining. Results: Among the following methods, the detection rate of acid-fast bacilli (AFB) by prior decontamination was more with Fluorescent (27%), followed by Ziehl Neelson(ZN) ( 25%) and then by Kinyoun staining (20%). Furthermore, post decontamination, the detection rate of AFB by post-NALC-NaOH method increased as the fluorescent method (37%), ZN (30%) and Kinyoun method (23%). Whereas the detection rate of AFB by post bleach method was less effective i.e. fluorescent staining (32%), ZN (26%), and Kinyoun (20%). Conclusion: The rate of detection and efficiency of acid-fast bacilli was found to be more with Flourescent staining. This research also highlighted the increase in the detection rate of AFB after decontamination with NALC-NaOH method as compared to the bleach method thus it aided in increasing detection of bacilli.