title: Diagnosis of latent tuberculosis infection in healthy young adults in a country with high tuberculosis burden and BCG vaccination at birth.
abstract: BACKGROUND
  One third of the world's population is thought to have latent tuberculosis infection (LTBI) with the potential for subsequent reactivation of disease. To better characterize this important population, studies comparing Tuberculin Skin Test (TST) and the new interferon-γ release assays including QuantiFERON®-TB Gold In-Tube (QFT-GIT) have been conducted in different parts of the world, but most of these have been in countries with a low incidence of tuberculosis (TB). The aim of this study was therefore to evaluate the use of QFT-GIT assay as compared with TST in the diagnosis of LTBI in Ethiopia, a country with a high burden of TB and routine BCG vaccination at birth.
  
  
  METHODS
  Healthy medical and paramedical male students at the Faculty of Medicine, Addis Ababa University, Ethiopia were enrolled into the study from December 2008 to February 2009. The TST and QFTG-IT assay were performed using standard methods.
  
  
  RESULTS
  The mean age of the study participants was 20.9 years. From a total of 107 study participants, 46.7% (95%CI: 37.0% to 56.6%) had a positive TST result (TST≥10 mm), 43.9% (95%CI: 34.3% to 53.9%) had a positive QFT-GIT assay result and 44.9% (95%CI: 35.2% to 54.8%) had BCG scar. There was strong agreement between TST (TST ≥10mm) and QFT-GIT assay (Kappa = 0.83, p value = 0.000).
  
  
  CONCLUSIONS
  The TST and QFT-GIT assay show similar efficacy for the diagnosis of LTBI in healthy young adults residing in Ethiopia, a country with high TB incidence.
authors.affiliation: Armauer Hansen Research Institute, Addis Ababa, Ethiopia. fitayehu@yahoo.com
authors.forename: Alemnew F
authors.initials: AF
authors.lastname: Dagnew
authors.forename: Jemal
authors.initials: J
authors.lastname: Hussein
authors.forename: Markos
authors.initials: M
authors.lastname: Abebe
authors.forename: Martha
authors.initials: M
authors.lastname: Zewdie
authors.forename: Adane
authors.initials: A
authors.lastname: Mihret
authors.forename: Ahmed
authors.initials: A
authors.lastname: Bedru
authors.forename: Menberework
authors.initials: M
authors.lastname: Chanyalew
authors.forename: Lawrence
authors.initials: L
authors.lastname: Yamuah
authors.forename: Girmay
authors.initials: G
authors.lastname: Medhin
authors.forename: Peter
authors.initials: P
authors.lastname: Bang
authors.forename: T Mark
authors.initials: TM
authors.lastname: Doherty
authors.forename: Asrat
authors.initials: A
authors.lastname: Hailu
authors.forename: Abraham
authors.initials: A
authors.lastname: Aseffa
mesh_terms: D001500:BCG Vaccine / Q000008:administration & dosage / Q000276:immunology*; D005002:Ethiopia / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007371:Interferon-gamma / Q000097:blood; D059425:Interferon-gamma Release Tests / Q000379:methods; D055985:Latent Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D009169:Mycobacterium tuberculosis / Q000502:physiology; D013334:Students; D014374:Tuberculin Test / Q000379:methods; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D014611:Vaccination; D055815:Young Adult
chemical_list: D001500:BCG Vaccine; D007371:Interferon-gamma