The role of genexpert in diagnosis of sputum-negative pulmonary tuberculosis

Abstract

Background The GeneXpert MTB/RIF assay is a new diagnostic test that depends on a real-time PCR analysis of the sample for diagnosis of tuberculosis (TB) and detection of rifampicin resistance. Aim The aim was to evaluate the role of role of GeneXpert in the diagnosis of sputum-negative pulmonary TB. Patients and methods This study included 30 patients suspected to have TB, with mean age being 45.5±17.7 years. All patients had clinical and radiological signs consistent with TB, positive tuberculin test results, and three negative Ziehl–Neelsen sputum smears. Patients having no or incomplete data were excluded from the study. Results This study included 30 patients suspected to be have TB, comprising 24 (80%) males and six (20%) females. Their age ranged from 18 to 70 years, with a mean age of 45.5±17.7 years. They were selected from the Chest Departments of Bab El-Sha’eria, Al-Hussein University, and El-Abbasia Chest Hospitals in the period from February 2017 to December 2017. All patients have clinical and radiological signs consistent with TB, positive tuberculin test results, and three negative Ziehl–Neelsen sputum smears. Our study showed that GeneXpert was positive in 11 (36.7%) patients and negative in 19 (63.3%) patients. Conclusion The GeneXpert assay can be used as a gold standard to diagnose TB. As it is sensitive and specific for diagnosing smear-negative pulmonary TB, the assay is faster than culture.