Application of Bleach Concentration Method in Tissue Samples Received for Diagnosis of Extra Pulmonary Tuberculosis Diagnosis

Extra pulmonary Tuberculosis (TB) comprises 15% of the total tuberculosis cases. In cases of suspected extrapulmonary tuberculosis, rapid and accurate laboratory diagnosis is of prime importance, since traditional techniques of detecting acid-fast bacilli have limitations. The major difficulty with mycobacteria in tissue samples is achieving optimal cell lysis. A comparison of two methods, pretreatment of tissue with 4% Sodium Hypochlorite in Bleach concentration method and pretreatment with petroff’s method before culture on Lowenstein Jensen medium, was conducted on 18 extrapulmonary tissue specimens collected from different sites of suspected TB patients to evaluate the use of Bleach concentration method in tissue samples. The aim of this study is to apply this method for demonstration of AFB in tissue samples obtained from extrapulmonary sites and to correlate with Ziehl Neelson staining and LJ culture. A total of 18 tissue samples were studied from clinically suspected cases of Extra pulmonary TB which included endometrial tissue (15), (1) from kidney and (1) from brain. All the samples were processed for conventional ZN staining, bleach concentration method, PCR and AFB culture on LJ media. Out of 18 samples none were suggestive for TB by ZN staining, while 1(5.55%) was positive by PCR, 3(16.66%) were suggestive by bleach concentration method and the same i.e. 3(16.66%) came positive on LJ culture hence confirming the method. However to the best of our knowledge this is the pioneer study applied to the tissue samples and the results of the present study shows improved detection of AFB.