Role of GeneXpert in Diagnosis of Smear Negative Pulmonary Tuberculosis

Abstract

Abstract Background Pulmonary TB considered as a global health problem with specific concern in developing countries that need rapid methods in diagnosis with accurate results. Objective To evaluate the diagnostic yield of GeneXpert assay in diagnosis of TB infection in patients with negative sputum smear. Methods A total 346 cases with suspect clinical and radiological finding for TB infection was subjected to direct sputum analysis under microscope to find acid fast bacilli (AFB); the negative smear then subjected to GeneXpet assay analysis and sputum culture on LJ media. Results All cases with negative GeneXpert results, had negative culture, while 45 cases of 50 that had positive GeneXpert assay finding showed positive culture. The diagnostic yield of test was excellent (94.7%). The sensitivity, specificity, PPV and NPV were 100, 89.8, 90 and 100 respectively. Conclusion The performance of GeneXpert assay in diagnosing TB among smear negative patients was reasonable, and may fast the decision of treatment.