title: [Sensitivity and specificity of the BCG scar reading].
abstract: OBJECTIVE
  To validate the BCG scar as a marker of BCG vaccination status.
  
  
  METHODS
  A cross-sectional survey was carried out among 53,348 schoolchildren aged 6-14 years who underwent BCG scar examination as part of a large BCG vaccine trial taking place in the city of Manaus, Brazil. Results of BCG scar reading were compared with information on vaccine status of their vaccination cards or provided by parents or guardians. Double-reading was performed in a sub-sample. Data analysis was conducted using Stata 7 and Kappa coefficient.
  
  
  RESULTS
  Of 52,348 schoolchildren studied, vaccine status information from parents/guardian letters was available for 29,254 and from vaccination cards for 4,947. There was found a high agreement between the double-readings of the scars (Kappa=0.81). When the agreement between letter and card information was the gold standard, the sensitivity of BCG scar readings was 96.6% (95%CI 96.0-97.1) and the specificity was 71.1% (95%CI 55.7-83.7). The sensitivity was 96.1%, 97.3% and 95.3% for children vaccinated up to one month of age, four months and one year, respectively.
  
  
  CONCLUSIONS
  Sensitivity and specificity did not show an association with the child's age at the scar reading. BCG scar was a good marker of BCG vaccination status regardless of age - from the first years of life up to 14 years old.
authors.affiliation: Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, BA, Brasil. susanmp@ufba.br
authors.forename: Susan M
authors.initials: SM
authors.lastname: Pereira
authors.forename: Ana L
authors.initials: AL
authors.lastname: Bierrenbach
authors.forename: Inês
authors.initials: I
authors.lastname: Dourado
authors.forename: Maurício L
authors.initials: ML
authors.lastname: Barreto
authors.forename: Maria Yury
authors.initials: MY
authors.lastname: Ichihara
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Hijjar
authors.forename: L C
authors.initials: LC
authors.lastname: Rodrigues
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D000367:Age Factors; D001500:BCG Vaccine / Q000008:administration & dosage*; D001938:Brazil; D002648:Child; D002921:Cicatrix; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007114:Immunization / Q000706:statistics & numerical data*; D007115:Immunization Schedule; D008297:Male; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000517:prevention & control*; D014611:Vaccination / Q000706:statistics & numerical data
chemical_list: D001500:BCG Vaccine
vernacular_title: Sensibilidade e especificidade da leitura da cicatriz vacinal do BCG.