Bleach optimization of sputum smear microscopy for pulmonary tuberculosis.

The Revised National Tuberculosis Control Programme (RNTCP) aims to improve case detection rates of tuberculosis to facilitate prompt recognition and treatment. The low case detection rates in the programme can be directly attributed to failure to screen patients with suspected tuberculosis and the low sensitivity of the direct smear microscopy method to detect cases among the fraction of patients that are screened. Apart from low sensitivity, this method also has other disadvantages including the increased risk of infection transmission to technicians. There are several methods that can be used to improve sensitivity, but their applicability in a national programme and in resource limited settings are limited. Bleach processing of sputum smears prior to microscopy may be a cheap and effective way to improve on the sensitivity of the direct smear. Four distinctive techniques of sputum smear processing using bleach are described in the review, with the variations in each technique, along with the sensitivity. An analysis of reports published earlier on the bleach method is also presented including a discussion on when and why the bleach method works.