title: [Concordance of tuberculin tests and Interferon gamma release assays in the prison population].
abstract: OBJECTIVE
  To study the agreement of Tuberculin Skin Tests (TST) and Interferon Gamma Release Assays (IGRA) when screening tuberculosis infection amongst inmates recently admitted to prison.
  
  
  METHODS
  Prospective study conducted in a prison during the months of May and June 2009. Inmates without a TB history, with previous TST negatives or without prior TSTs were included. Participants signed an informed consent form and the study was approved by an independent Ethical Committee. TST (positive 10 > or = mm) and IGRA (Quantiferon TB-Gold) were performed and standardized data collection was carried out. The agreement between both tests was analysed using the Kappa index.
  
  
  RESULTS
  A total of 181 people were included. 62% were foreign-born, 17% had previous BCG vaccination, 8.4% were IDUs and 4% HIV-infected. Foreign born subjects were more frequently vaccinated and presented less drug use and HIV infection than people born in Spain. (p=0.02, p=0.02 and p=0.01 respectively). TST results were positive in 24% and IGRA in 26%. Both tests were performed in 149 people (82%). Discordant results were observed in 15.8%. Agreement of the Kappa coefficient was 0.6 (CI 0.4-0.7). Agreement was better in the native population (K=0.8) and worse in BCG vaccinated (K=0.4) and foreign-born subjects (K=0.8).
  
  
  CONCLUSIONS
  Overall agreement was moderate and was less amongst vaccinated subjects and those born abroad. Extension of the study could be useful to evaluate which test better predicts the risk of progression to active TB and the cost-benefit of both tests among the prison population.
authors.affiliation: Servicios Médicos, Centro Penitenciario de Hombres de Barcelona, Barcelona, España. andres.marco.m@gmail.com
authors.forename: A
authors.initials: A
authors.lastname: Marco Mouriño
authors.forename: A
authors.initials: A
authors.lastname: Orcau Palau
authors.forename: R
authors.initials: R
authors.lastname: Jané Galliga
authors.forename: M
authors.initials: M
authors.lastname: Escribano Ibáñez
authors.forename: J A
authors.initials: JA
authors.lastname: Caylà Buqueras
authors.forename: N
authors.initials: N
authors.lastname: Solé Zapata
authors.forename: L
authors.initials: L
authors.lastname: del Baño Hollín
authors.forename: S
authors.initials: S
authors.lastname: Quintero del Río
authors.forename: M D
authors.initials: MD
authors.lastname: Ferrer Escobar
authors.forename: J
authors.initials: J
authors.lastname: Mangues Bafalluy
authors.forename: R A
authors.initials: RA
authors.lastname: Guerrero Moreno
authors.forename: V
authors.initials: V
authors.lastname: Martín Sánchez
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D006801:Humans; D007371:Interferon-gamma / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011329:Prisoners; D011446:Prospective Studies; D014374:Tuberculin Test; D014376:Tuberculosis / Q000097:blood* / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D007371:Interferon-gamma