title: Smear plus Detect-TB for a sensitive diagnosis of pulmonary tuberculosis: a cost-effectiveness analysis in an incarcerated population.
abstract: BACKGROUND
  Prison conditions can favor the spread of tuberculosis (TB). This study aimed to evaluate in a Brazilian prison: the performance and accuracy of smear, culture and Detect-TB; performance of smear plus culture and smear plus Detect-TB, according to different TB prevalence rates; and the cost-effectiveness of these procedures for pulmonary tuberculosis (PTB) diagnosis.
  
  
  METHODS
  This paper describes a cost-effectiveness study. A decision analytic model was developed to estimate the costs and cost-effectiveness of five routine diagnostic procedures for diagnosis of PTB using sputum specimens: a) Smear alone, b) Culture alone, c) Detect-TB alone, d) Smear plus culture and e) Smear plus Detect-TB. The cost-effectiveness ratio of costs were evaluated per correctly diagnosed TB case and all procedures costs were attributed based on the procedure costs adopted by the Brazilian Public Health System.
  
  
  RESULTS
  A total of 294 spontaneous sputum specimens from patients suspected of having TB were analyzed. The sensibility and specificity were calculated to be 47% and 100% for smear; 93% and 100%, for culture; 74% and 95%, for Detect-TB; 96% and 100%, for smear plus culture; and 86% and 95%, for smear plus Detect-TB. The negative and positive predictive values for smear plus Detect-TB, according to different TB prevalence rates, ranged from 83 to 99% and 48 to 96%, respectively. In a cost-effectiveness analysis, smear was both less costly and less effective than the other strategies. Culture and smear plus culture were more effective but more costly than the other strategies. Smear plus Detect-TB was the most cost-effective method.
  
  
  CONCLUSIONS
  The Detect-TB evinced to be sensitive and effective for the PTB diagnosis when applied with smear microscopy. Diagnostic methods should be improved to increase TB case detection. To support rational decisions about the implementation of such techniques, cost-effectiveness studies are essential, including in prisons, which are known for health care assessment problems.
authors.affiliation: Centro de Desenvolvimento Científico e Tecnológico (CDCT), Fundação Estadual de Produção e Pesquisa em Saúde (FEPPS), Av. Ipiranga 5400, 3° andar, CEP 90610-000, Porto Alegre, Rio Grande do Sul, Brazil. karen.schmid@gmail.com.
authors.forename: Karen Barros
authors.initials: KB
authors.lastname: Schmid
authors.affiliation: Universidade Luterana do Brasil (ULBRA), Canoas, Brazil. luciene.scherer@hotmail.com.
authors.forename: Luciene
authors.initials: L
authors.lastname: Scherer
authors.affiliation: Centro de Desenvolvimento Científico e Tecnológico (CDCT), Fundação Estadual de Produção e Pesquisa em Saúde (FEPPS), Av. Ipiranga 5400, 3° andar, CEP 90610-000, Porto Alegre, Rio Grande do Sul, Brazil. reginabbarcellos@gmail.com.
authors.forename: Regina Bones
authors.initials: RB
authors.lastname: Barcellos
authors.affiliation: Programa Nacional de Controle da Tuberculose - Secretaria de Vigilância em Saúde/Ministério da Saúde, Porto Alegre, Brazil. danielekuhleis@hotmail.com.
authors.forename: Daniele
authors.initials: D
authors.lastname: Kuhleis
authors.affiliation: Programa de Pós-graduação em Epidemiologia da Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil. ppgepid@ufrgs.br.
authors.forename: Isaías Valente
authors.initials: IV
authors.lastname: Prestes
authors.affiliation: Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil. ricardo.steffen@gmail.com.
authors.forename: Ricardo Ewbank
authors.initials: RE
authors.lastname: Steffen
authors.affiliation: Centro de Desenvolvimento Científico e Tecnológico (CDCT), Fundação Estadual de Produção e Pesquisa em Saúde (FEPPS), Av. Ipiranga 5400, 3° andar, CEP 90610-000, Porto Alegre, Rio Grande do Sul, Brazil. dallacostaer@gmail.com.
authors.forename: Elis Regina
authors.initials: ER
authors.lastname: Dalla Costa
authors.affiliation: Centro de Desenvolvimento Científico e Tecnológico (CDCT), Fundação Estadual de Produção e Pesquisa em Saúde (FEPPS), Av. Ipiranga 5400, 3° andar, CEP 90610-000, Porto Alegre, Rio Grande do Sul, Brazil. mrossett@terra.com.br.|Universidade Luterana do Brasil (ULBRA), Canoas, Brazil. mrossett@terra.com.br.
authors.forename: Maria Lucia Rosa
authors.initials: ML
authors.lastname: Rossetti
mesh_terms: D001938:Brazil / Q000453:epidemiology; D003362:Cost-Benefit Analysis; D003661:Decision Support Techniques; D005260:Female; D017048:Health Care Costs / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D018803:Models, Economic; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D011329:Prisoners; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000191:economics / Q000453:epidemiology