title: The role of latex agglutination test for the etiological diagnosis of pleural effusion in children and adolescents.
abstract: BACKGROUND
  The etiological diagnosis of pleural effusion is a difficult task because the diagnostic tools can only establish a definitive etiological diagnosis in at most 76% of cases.
  
  
  OBJECTIVE
  To verify the diagnostic accuracy of the latex agglutination test (LAT) for the etiological diagnosis of pleural effusions caused by Streptococcus pneumoniae and Haemophilus influenzae type b.
  
  
  METHODS
  After thoracocentesis, paired fresh samples of pleural fluid from 418 children and adolescents were included in this investigation. They were tested blindly and simultaneously through counterimmunoelectrophoresis (CIE) and LAT for both bacteria. Sensitivity, specificity, predictive values and likelihood ratios (LR) were calculated taking CIE as a reference standard.
  
  
  RESULTS
  The sensitivity and specificity of LAT was 100% (95% confidence interval, 94.4%-100%) and 83.3% (95% confidence interval, 79.0%-87.0%), respectively, whereas the positive (calculated from Bayes' theorem) and negative predictive values were, respectively, lower than 1% and 100% (95% confidence interval, 98.8%-100%). Positive and negative LR were 6.0 (95% confidence interval, 4.7-7.6) and zero, respectively.
  
  
  CONCLUSIONS
  Our results suggest that LAT is a useful tool for the etiological diagnosis of pleural effusion. It is a reliable, rapid, simple to perform and shows an excellent yield in our studied population, helping to prescribe appropriate antibiotics for this clinical condition.
authors.affiliation: Department of Pediatrics, Federal University of Minas Gerais, Medical School, Belo Horizonte, Brazil.
authors.forename: Paulo
authors.initials: P
authors.lastname: Camargos
authors.affiliation: Child Health Division, Belo Horizonte Municipal Health Authority, Belo Horizonte, Brazil.
authors.forename: Ana Cristina
authors.initials: AC
authors.lastname: Fonseca
authors.affiliation: Department of Pediatrics, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil.
authors.forename: Sérgio
authors.initials: S
authors.lastname: Amantéa
authors.affiliation: Department of Pediatrics, Federal University of Minas Gerais, Medical School, Belo Horizonte, Brazil.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Oliveira
authors.affiliation: Epidemiology and Diseases Control Division, Public Health System Central Laboratory, Ezequiel Dias Foundation, Belo Horizonte, Brazil.
authors.forename: Maria das Graças
authors.initials: MDG
authors.lastname: Benfica
authors.affiliation: Epidemiology and Diseases Control Division, Public Health System Central Laboratory, Ezequiel Dias Foundation, Belo Horizonte, Brazil.
authors.forename: Chequer
authors.initials: C
authors.lastname: Chamone
mesh_terms: D000293:Adolescent; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003378:Counterimmunoelectrophoresis / Q000379:methods*; D005122:Exudates and Transudates / Q000276:immunology* / Q000382:microbiology; D005260:Female; D019741:Haemophilus influenzae type b / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007841:Latex Fixation Tests / Q000379:methods*; D008297:Male; D010996:Pleural Effusion / Q000175:diagnosis* / Q000209:etiology / Q000382:microbiology / Q000821:virology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013296:Streptococcus pneumoniae / Q000302:isolation & purification; D000069258:Thoracentesis / Q000379:methods
keywords: latex agglutination test - pleural effusion - pleural effusion management - empyema - pediatric empyema