title: Quantiferon TB-Gold conversion can predict active tuberculosis development in elderly nursing home residents.
abstract: OBJECTIVE
  The study was carried out on elderly nursing home residents in Taiwan. We assessed whether the serial QuantiFERON-TB Gold (QFT-G) assay and serial tuberculin skin test (TST) were reliable tools to predict or exclude the development of active tuberculosis (TB).
  
  
  METHODS
  This prospective observational cohort study involved non-bacillus Calmette-Guérin-vaccinated 259 elderly nursing home residents free of active TB at baseline. Of these, 147 were eligible for follow up. Participants underwent serial QFT-G and TST at baseline and 2-year follow up, and were monitored for active TB over 5 years. Agreement between QFT-G and TST, incidence rate ratio, positive predictive value, and negative predictive value for progression to active TB were measured.
  
  
  RESULTS
  During 5-year follow up, three participants developed active TB. The agreement between these two tests was 54.13% (ĸ = 0.167, P = 0.001). The incidence rate ratio was 15.8 (P = 0.016) for the QFT-G-conversion group compared with the TST-positive group at baseline. Positive predictive value for QFT-G conversion groups was 25%. Negative predictive value was 100% for the TST-negative group at baseline.
  
  
  CONCLUSIONS
  In the elderly nursing home residents, QFT-G conversion is a more reliable tool to predict the development of active TB. Meanwhile, TST is a valuable tool for predicting the chance of not developing active TB.
authors.affiliation: Division of Chest Medicine, Department of Internal Medicine, National Taiwan University Hospital, Hsin-Chu, Taiwan.|Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu, Taiwan.
authors.forename: Ping-Hsien
authors.initials: PH
authors.lastname: Tsou
authors.affiliation: Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.|Department of Medical Technology, Jen-The Junior College of Medicine, Nursing and Management, Miaoli, Taiwan.
authors.forename: Wei-Chang
authors.initials: WC
authors.lastname: Huang
authors.affiliation: Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, Taichung Hospital, Ministry of Health and Welfare, Taichung, Taiwan.
authors.forename: Chen-Cheng
authors.initials: CC
authors.lastname: Huang
authors.affiliation: Department of Microbiology, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Chen-Fu
authors.initials: CF
authors.lastname: Lin
authors.affiliation: Reference Medical Laboratory, Taichung, Taiwan.
authors.forename: Kun-Ming
authors.initials: KM
authors.lastname: Wu
authors.affiliation: Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Jeng-Yuan
authors.initials: JY
authors.lastname: Hsu
authors.affiliation: Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.|Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan.|Institute of Respiratory Therapy, China Medical University, Taichung, Taiwan.
authors.forename: Gwan-Han
authors.initials: GH
authors.lastname: Shen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009735:Nursing Homes; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013624:Taiwan; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology
keywords: Mycobacterium tuberculosis; Quantiferon TB-Gold assay; elderly; nursing home residents; tuberculin skin test