Open AccessTHE VALUE OF FLUORESCENT MICROSCOPY AND BLEACH SEDIMENTATION METHOD FOR DETECTION OF SMEAR NEGATIVE TUBERCULOSIS
Author(s) -
G Amare,
U Chandrashekhar,
W Mulugeta,
M Anteneh,
S Abubeker,
I Khadir,
G Muluwork,
D Kassu
Publication year - 2013
Publication title -
international journal of microbiology research
Language(s) - English
Resource type - Journals
eISSN - 0975-9174
pISSN - 0975-5276
DOI - 10.9735/0975-5276.5.1.336-340
Subject(s) - bleach , fluorescence , sedimentation , tuberculosis , microscopy , fluorescence microscope , materials science , chemistry , medicine , pathology , biology , optics , physics , organic chemistry , paleontology , sediment
The diagnosis of tuberculosis in developing countries has been done by direct microscopic examination which has low sensitivity. Most of the patients with TB are detected as free of TB. For the low sensitivity of the directed microscopy, a new high sensitive fluorescent microscope was developed. In addition bleach sedimentation technique increased the sensitivity of both direct and fluorescent techniques. This investigation was undertaken to evaluate the value of fluorescent microscopy and bleach sedimentation method for the detection of smear negative tuberculosis cases in sputum sample in comparison with direct microscopy.A total of 132 sputum samples from patients aged 7 to 75 years were examined during the study period. Culture (Gold standard) result identified 75 subjects as positive. Among 75 cultures positive sputum samples direct Ziehl Neilson technique identified 50 samples as positive with sensitivity of 66% and specificity of 98.2%. In fluorescent microscopy 55 of them were identified as positive with sensitivity of 78.6% and specificity of 80.7% in comparison with culture. On the other hand over night bleach sedimentation in Ziehl Neilson technique has increased the sensitivity to 76% and resulted in specificity of 91.2%. Bleach fluorescent microscopy has increased the sensitivity to 82.7% and resulted in specificity of 80.7% in comparison with culture. From the total of 132 samples 81 were smear negative samples as confirmed by direct microscopy. From these 81 samples direct fluorescent microscopy has identified 12 samples as positive out of 25 culture positive samples with sensitivity of 48% and specificity of 80.3%. Bleach direct microscopy has identified 8 positive with sensitivity of 32% and specificity of 89.3%. Bleach fluorescent microscopy identified 13 as positive with sensitivity of 52% and specificity of 82%. Therefore, the combination of bleach sedimentation and florescent microscopy can be used as a diagnostic tool for the reduction of morbidity and mortality occurring from Tuberculosis and can be used for early diagnosis and treatment of the disease