The bacteriological diagnosis of tuberculosis (TB) is largely dependent on the Ziehl-Neelsen (ZN) microscopy. This method has a low sensitivity, which can be improved by the concentration of the specimen with sodium hypochlorite or Bleach (NaOCl), followed by sedimentation after doing LED. This study was conducted to evaluate the efficiency of bleach sedimentation technique in detection of Mycobacterium tuberculosis by LED microscopy. A Total of 100 sputum samples from the patients who visited RNTCP of Rama Medical College Hospital and Research Centre between April 2015 and March 2016. Morning samples were collected from each patient, direct smears were prepared and they were stained with the ZN Stain and aura LED technique and the remaining samples were concentrated by using 3.5% NaOCl, followed by sedimentation and staining with ZN stain and aura LED stain. The improvement in the sensitivity following the bleach method was studied. Out of 100 sputum samples, 50 smear positive samples by ZN showed 100% positivity but increase the grading of positive result after the bleach sedimentation technique in both LED and ZN microscopy while 50 AFB negative samples shows 12% positivity rate was ZN for bleach and 26% shows positivity rate was using aura LED for bleach sedimentation technique. Whereas the overall positivity rate was 56% shows by ZN for bleach and 63% shows positivity rate was using aura LED for bleach sedimentation technique. A statistically significant (p < 0.0001) increase in the positivity with the use of the bleach method was detected as compared to that with the use of the direct ZN staining and aura LED Method. After bleach for LED is sensitivity, specificity, positive predictive value (PPV), and the negative predictive value (NPV) were 100%, 89.3%, 90.3%and 100% respectively with a 95% confidence interval, with the use of the 3.5% NaOCl method. In the present study, the Bleach sedimentation method increases the positivity in aura LED microscopy when it was compared with the ZN microscopy The bleach method has advantages over the direct method, as it is simple and as it does not require any additional expertise beyond that which is required for the conventional direct smear microscopy. The materials and the reagents are also affordable and they are available locally.

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