title: GeneXpert MTB/RIF Testing in the Management of Patients with Active Tuberculosis; A Real Life Experience from Saudi Arabia.
abstract: BACKGROUND
  GeneXpert MTB/RIF is a real-time PCR assay with established diagnostic performance in pulmonary and extra-pulmonary forms of tuberculosis. The aim of this study was to assess the contribution of GeneXpert MTB/RIF assay to the management of patients with any form of active tuberculosis in a single large tertiary center in Saudi Arabia, with a special focus on the impact on time to start of antituberculous therapy compared with Ziehl-Neelsen (ZN) smears and mycobacterial cultures.
  
  
  METHODS
  Clinical, radiological and laboratory records for all patients who were commenced on antituberculous therapy between March 2011 and February 2013 were retrospectively reviewed.
  
  
  RESULTS
  A total of 140 patients were included, 38.6% of which had pulmonary tuberculosis. GeneXpert MTB/RIF was requested for only 39.2% of patients and was the only reason for starting antituberculous therapy for only 12.1%. The median time to a positive GeneXpert MTB/RIF result was 0 days (IQR 3) compared with 0 day (IQR 1) for smear microscopy (P > 0.999) and 22 days (IQR 21) for mycobacterial cultures (P < 0.001). No patients discontinued antituberculous therapy because of a negative GeneXpert MTB/RIF result.
  
  
  CONCLUSIONS
  In a setting wherein physicians are highly experienced in the diagnosis and treatment of tuberculosis, GeneXpert MTB/RIF was remarkably under-utilized and had only a limited impact on decisions related to starting or stopping antituberculous therapy. Cost-effectiveness and clinical utility of routine testing of all smear-negative clinical samples submitted for tuberculosis investigations by GeneXpert MTB/RIF warrant further study.
authors.affiliation: Division of Infectious Diseases, Prince Sultan Military Medical City, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Ali S
authors.initials: AS
authors.lastname: Omrani
authors.affiliation: Department of Medicine, Prince Sultan Military Medical City, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Mohammed F
authors.initials: MF
authors.lastname: Al-Otaibi
authors.affiliation: Division of Microbiology, Prince Sultan Military Medical City, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Souad M
authors.initials: SM
authors.lastname: Al-Ateah
authors.affiliation: Department of Medicine, Prince Sultan Military Medical City, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Fahad M
authors.initials: FM
authors.lastname: Al-Onazi
authors.affiliation: Department of Infection Prevention and Control, Prince Sultan Military Medical City, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Kamran
authors.initials: K
authors.lastname: Baig
authors.affiliation: Division of Microbiology, Prince Sultan Military Medical City, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Noura A
authors.initials: NA
authors.lastname: El-Khizzi
authors.affiliation: Division of Infectious Diseases, Prince Sultan Military Medical City, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Ali M
authors.initials: AM
authors.lastname: Albarrak
keywords: GeneXpert MTB/RIF; Saudi Arabia; Tuberculosis