Diagnostic Value Of Gene-Xpert and Ziehl-Neelsen in the Detection of Pulmonary Tuberculosis

Background: Accuracy and quick diagnosis of tuberculosis (TB) is the base to the effective treatment and management. Culture using Lowenstein-Jensen (LJ) medium is considered the gold standard for the diagnosis of TB. The delay in the diagnosis increases the transmission opportunities to others and also the emergence of multidrug resistant TB. Newly administered Gene-Xpert MTB/RIF assay takes only a couple of hours to give the results and provide data about rifampicin resistance at the same time. Purpose: This study aimed to evaluate the diagnostic value of both Gene-Xpert in TB and Zeil-Neelson (ZN) stain versus the LJ culture in pulmonary TB. Drug susceptibility tests (DST) for first line anti-TB drugs was also performed for the resistant patients. Methods: This observational study was conducted on 100 TB persons presented to the hospital. Diagnosis of tuberculosis depended on the examination of sputum samples with Zeil-Neelson stain, Gene-Xpert test and LJ culture. Results: Hb level and RBCs count were found to be significantly lower in TB patients when compared to “No TB” patients. ZN smear positivity for TB was 55% and for Gene-Xpert was 66% of confirmed TB diagnosed cases. Sensitivity and negative predictive value of Gene-Xpert were 95.5% and 91.5%, respectively which are significantly higher as compared to ZN in which sensitivity and negative predictive value were 78.8% and 68.5%, respectively. Conclusion: The present study concluded that Gene-Xpert is considered a more sensitive tool than ZN stain in the early diagnosis of pulmonary tuberculosis.