title: Diagnosis of latent Mycobacterium tuberculosis infection: tuberculin test versus interferon-gamma release.
abstract: BACKGROUND
  The treatment of individuals with active tuberculosis (TB) and the identification and treatment of latent tuberculosis infection (LTBI) contacts are the two most important strategies for the control of TB. The objective of this study was compare the performance of tuberculin skin testing (TST) with QuantiFERON-TB Gold In TUBE(r) in the diagnosis of LTBI in contacts of patients with active TB.
  
  
  METHODS
  Cross-sectional analytical study with 60 contacts of patients with active pulmonary TB. A blood sample of each contact was taken for interferon-gamma release assay (IGRA) and subsequently performed the TST. A receiver operating characteristic curve was generated to assess the cutoff points and the sensitivity, predictive values, and accuracy were calculated. The agreement between IGRA and TST results was evaluated by Kappa coefficient.
  
  
  RESULTS
  Here, 67.9% sensitivity, 84.4% specificity, 79.1% PPV, 75% NPV, and 76.7% accuracy were observed for the 5mm cutoff point. The prevalence of LTBI determined by TST and IGRA was 40% and 46.7%, respectively.
  
  
  CONCLUSIONS
  Both QuantiFERON-TB Gold In TUBE(r) and TST showed good performance in LTBI diagnosis. The creation of specific diagnostic methods is necessary for the diagnosis of LTBI with higher sensitivity and specificity, preferably with low cost and not require a return visit for reading because with early treatment of latent forms can prevent active TB.
authors.affiliation: Programa de Pós-Graduação Stricto Sensu em Saúde Coletiva, Universidade Federal do Maranhão, São Luís, Maranhão, Brazil.
authors.forename: Thaís Furtado
authors.initials: TF
authors.lastname: Ferreira
authors.affiliation: Programa de Pós-Graduação Stricto Sensu em Saúde Coletiva, Universidade Federal do Maranhão, São Luís, Maranhão, Brazil.
authors.forename: Pollyanna da Fonseca Silva
authors.initials: Pda F
authors.lastname: Matsuoka
authors.affiliation: Programa de Pós-Graduação Stricto Sensu em Saúde Coletiva, Universidade Federal do Maranhão, São Luís, Maranhão, Brazil.
authors.forename: Alcione Miranda Dos
authors.initials: AM
authors.lastname: Santos
authors.affiliation: Programa de Pós-Graduação Stricto Sensu em Saúde Coletiva, Universidade Federal do Maranhão, São Luís, Maranhão, Brazil.
authors.forename: Arlene de Jesus Mendes
authors.initials: Ade J
authors.lastname: Caldas
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D059425:Interferon-gamma Release Tests; D055985:Latent Tuberculosis / Q000175:diagnosis*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014374:Tuberculin Test