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.

Application of bleach method in diagnosis of extra-pulmonary tuberculosis.

Extra pulmonary tuberculosis (TB) comprises 15% of the total tuberculosis cases. Bleach concentration method for demonstration of Acid fast bacilli (AFB) has been recently described for sputum. The aim of this study is to apply this method for demonstration of AFB in material obtained from extra-pulmonary sites and to correlate with cytology and conventional Ziehl Neelsen (Z N) staining. A total of 55 samples were studied from clinically suspected cases of extrapulmonary TB which included, FNA lymph nodes (17), abscesses drained from various body parts (18), body fluids (18) and skin scrapping (2). All the samples were processed for routine cytology, conventional ZN staining and bleach method followed by ZN staining. Out of 55 samples, 24(43.40%) were indicative of tuberculosis on cytology, 12(21.8%) were positive for AFB on conventional ZN staining, while the positivity increased to 39(70.90%) by Bleach method. Bleach solution is inexpensive and readily available in hospitals and its application has been proved in pulmonary tuberculosis. However to the best of our knowledge this is a pioneer study applied to the extra-pulmonary samples and the results of the present study shows improved detection of AFB.