title: Diagnostic Utility of QuantiFERON-TB Gold (QFT-G) in Active Pulmonary Tuberculosis.
abstract: BACKGROUND
  The utility of QuantiFERON-TB Gold In-Tube (QFT-G) test in the diagnosis of tuberculosis disease has been validated in high and low tuberculosis-prevalent (TB) countries.
  
  
  OBJECTIVE
  The aim of this study is to assess the performance of the QFT-G test in the diagnosis of tuberculosis disease among tuberculosis patients in an intermediate prevalent country.
  
  
  METHODS
  A retrospective study at the King Abdulaziz Medical City-Riyadh (KAMC-R).
  
  
  METHODS
  We retrospectively reviewed all the patients with a diagnosis of pneumonia, including tuberculosis, admitted to KAMC-R between 1 January 2009 and 31 December 2013. We included only patients with an available result of the QFT-G test. A total of 142 tuberculosis cases and 226 pneumonia cases were studied, to assess the utility of the QFT-G test in diagnosing tuberculosis cases.
  
  
  RESULTS
  Among the tuberculosis (n = 142) cases, the QFT-G tested positive in 68.3%, negative in 23.2%, and indeterminate in 12 cases (8.5%). Of the 226 pneumonia cases, the QFT-G tested positive in only 20.4%, while a majority of 66.4% tested negative, with 30 cases (13.3%) being indeterminate. When we excluded 42 patients with indeterminate results, the QFT-G test achieved a sensitivity of 74.6% [95% CI: 66.09 to 81.65%] and specificity of 76.53 % [95% CI: 69.85 to 82.15%] in the diagnosis of tuberculosis cases.
  
  
  CONCLUSIONS
  This study concludes that the QFT-G test is a useful tool for detecting tuberculosis disease when used as an adjunct tool for the diagnosis of active TB cases. It certainly cannot be used solely and indiscriminately, separate from other clinical and radiological information, in the diagnosis of active tuberculosis cases.
authors.affiliation: King Abdullah International Medical Research Center/College of Public Health and Health Informatics, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Anwar
authors.affiliation: Department of Medicine, Pulmonary Division-ICU, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Al-Jahdali
authors.initials: AJ
authors.lastname: Hamdan
authors.affiliation: Department of Medicine, Pulmonary Division-ICU, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Baharoon
authors.initials: B
authors.lastname: Salim
authors.affiliation: King Abdullah International Medical Research Center/College of Public Health and Health Informatics, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Ali
authors.initials: A
authors.lastname: Yosra
authors.affiliation: The George Washington University, Washington, DC, USA.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Hani
authors.affiliation: Department of Medicine, Pulmonary Division-ICU, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Al-Harbi
authors.initials: AH
authors.lastname: Abdullah
keywords: Pneumonia; QFT-G; QuantiFERON; Tuberculosis