Comparative Evaluation of Different Microscopic Methods with the Conventional Culture for the Diagnosis of Pulmonary Tuberculosis in a Teaching Hospital

Tuberculosis is regarded as the greatest cause of death worldwide. In the developing countries including India, population, poverty, malnutrition, and highly congested environment increased the substantial risk for infection with Mycobacterium tuberculosis. The principal obstacle in the cure of tuberculosis is the inaccurate diagnosis as well as prolonged treatment. Therefore, a study was carried out in order to evaluate the results obtained by both the light microscopy and fluorescent microscopy with the Lowenstein-Jensen (LJ) culture method for detection of Mycobacterium tuberculosis in clinical samples. Among two hundred and one samples, 50 (24.8%) AFB+ results were found by light microscopy and 70 (34.8%) AFB+ were found by fluorescence microscopy. On LJ culture media, 84(41.7%) AFB+ isolates were obtained, which reveals that culture remains the gold standard for diagnosis of tuberculosis. Significantly, the sensitivity and specificity of fluorescence microscopy was higher than light microscopy compared to culture. To overcome this situation, it is suggested that a combination of smear and culture would diagnose more patients of tuberculosis in resource constraint settings.