Comparison of staining techniques-Ziehl Neelsen stain, Gabbet's Stain, Fluorochrome stain for detection of mycobacterium tuberculosis in sputum

In developing countries, Ziehl-Neelsen (Z-N) sputum smear microscopy is widely used. The present prospective study was under taken to see the efficacy of Ziehl-Neelson method versus Gabbett and Fluorescent staining in the detection of mycobacteria in sputum sample. 80 sputum samples were collected from suspected tuberculosis patients attending RNTCP OPD at, Nerul, Navi Mumbai. Triplicate smears were prepared from all these samples and stained by the Z-N, Gabbet's, and Fluorescent stain. Number of smears positive for Acid Fast Bacilli by, Z-N method 13(16%), Gabbett's method 7(9%), Fluorescent method 26(33%). Combination of two staining methods yielded following results: Z-N + Fluorescent26 (33%) and Z-N + Gabbett 13(16%). The conclusion from this study is that when smear examination by Z-N is done, there are possibilities of false negative results which can be reduced by using Fluorescent staining. The rate of positivity can be improved by combination of Z-N + Fluorescent staining. So, it may be concluded that combination of ZN and Fluorescent Microscopy may be considered for diagnosis of pulmonary tuberculosis in any diagnostic set up along with culture which is the gold standard.