Role of Histopathology, Cytopathology and Bleach Sedimentation Technique in the 'Diagnosis of Tuberculosis

Abstract

Tuberculosis remains a major threat to world health. About one third of the world's populations are suffering from this dreadful disease. Approximately 8 to IO million new cases of tuberculosis occur and about 3 million people die annually from this disease. The incidence of TB continues to rise especially in developing countries including Bangladesh where more than 90% of the global TB cases and deaths occur. After HIV; tuberculosis is the leading infectious causes of death in the world. Laboratory procedure is essential for diagnosis as well as for treatment of tuberculosis. Microscopy of smears made directly from sputum for detection of AFB is the most commonly used method for diagnosis of tuberculosis. However, microscopy of smears made directly from sputum has a low sensitivity and requires the presence of 5000-10000 organisms per ml. Thus, reliance on smear microscopy may cause missed or delayed tuberculosis diagnosis, potentially increasing morbidity, mortality and tuberculosis transmission. Increasing the sensitivity of tuberculosis diagnostic testing is a public health priority and there is an urgent need for improved methods. We have compared microscopy of smear made directly from sputum with microscopy of sputum made after liquefaction and concentration of sputum with household bleach. Diagnosis of tuberculosis is often difficult to diagnose specially when no acid-fast bacilli (AFB) seen in sputum and no pulmonary lesion seen radiologically. In such situations, Histopathological or cytopathological examination is helpful for diagnosis of tuberculosis. These methods are reliable and reasonably safe and have increased value in terms of diagnostic accuracy, sensitivity and specificity.