Application of bleach method to improve sputum smear microscopy for the diagnosis of pulmonary tuberculosis

In an active surveillance study, the bleach concentration method to improve sputum smear microscopy for the diagnosis of pulmonary tuberculosis was applied in chest symptomatics in Mahidpur block of Ujjain district in Madhya Pradesh, India. We purposely selected twenty villages with population of approximately 20,000 individuals. 664 sputum specimens from 297 chest symptomatics were collected. Ziehl-Neelsen staining was performed on direct sputum smears, smears made after bleach method and modified Petroff's method. Out of 297 chest symptomatics, 16 cases (5.38%) were positive by direct microscopy, 27 cases (9.09%) were positive by bleach method, 22 cases (7.40%) were positive by modified Petroff's method. The bleach method is safe, cheap, easy and sensitive. It can be applied for improved detection of Mycobacterium tuberculosis in hospitals and laboratories especially in settings where mycobacterial culture facilities are not available. The implementation of bleach method clearly improves case detection and can be a useful contribution in the National Tuberculosis Control Program.