title: The clinical utility of tuberculin skin test and interferon-γ release assay in the diagnosis of active tuberculosis among young adults: a prospective observational study.
abstract: BACKGROUND
  The roles of the tuberculin skin test (TST) and QuantiFERON®-TB Gold In-Tube assay (QFT-IT) in the diagnosis of active tuberculosis (TB) are not clear in young adults. We evaluated the diagnostic accuracy of the TST and QFT-IT in smear-negative TB among young adults with no underlying disease.
  
  
  METHODS
  We prospectively enrolled 166 young participants 20-29 years of age with suspected active TB in a military hospital of South Korea. The TST and QFT-IT were performed for all participants.
  
  
  RESULTS
  Of the 143 patients included in the analysis, active TB was diagnosed in 100 (69.9%). There were 141 male patients, none of whom had immunosuppressive disease. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of TST were 94% (95% CI, 87-98%), 88% (95% CI, 74-96%), 95% (95% CI, 88-98%), and 86% (95% CI, 72-94%), respectively. The sensitivity, specificity, PPV, and NPV of the QFT-IT were 93% (95% CI, 86-97%), 95% (95% CI, 81-99%), 98% (95% CI, 92-99%), and 84% (95% CI, 69-93%), respectively. No significant differences were found between the TST and QFT-IT in any statistic.
  
  
  CONCLUSIONS
  Both the TST and QFT-IT showed high sensitivity and specificity in differentiating active TB from other diseases. The diagnostic accuracy of these two tests did not differ significantly when applied to this clinical population of young, immunocompetent adults in whom neonatal BCG vaccination was common, there was no history of previous TB and in whom suspicion of TB was high.
  
  
  BACKGROUND
  ClinicalTrials.gov: NCT00982969.
authors.affiliation: Department of Internal Medicine, Armed Forces Capital Hospital, Seongnam-si, Gyeonggi-do, Republic of Korea.
authors.forename: Ji Eun
authors.initials: JE
authors.lastname: Lee
authors.forename: Hee-Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Sei Won
authors.initials: SW
authors.lastname: Lee
mesh_terms: D000328:Adult; D019411:Clinical Laboratory Techniques / Q000379:methods*; D006801:Humans; D007372:Interferons / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008297:Male; D008889:Military Personnel; D011446:Prospective Studies; D056910:Republic of Korea; D012680:Sensitivity and Specificity; D012882:Skin Tests / Q000379:methods; D014374:Tuberculin Test / Q000379:methods; D014376:Tuberculosis / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D007372:Interferons