title: Role of adenosine deaminase and the influence of age on the diagnosis of pleural tuberculosis.
abstract: OBJECTIVE
  1) To determine factors affecting adenosine deaminase (ADA) levels in pleural fluid (PF), and 2) to establish the optimal ADA cut-off level for a Brazilian population.
  
  
  METHODS
  ADA levels in PF of 309 patients were analysed to investigate pleural effusion. All patients were evaluated for age, sex and presence of tuberculosis (TB) based on a positive pleural biopsy. Differences in ADA levels between groups were analysed using Kruskal-Wallis one-way analysis of variance. Logistic regression analysis was also carried out to predict the occurrence of TB. ADA cut-off levels were selected using the receiver operating characteristic (ROC) curve.
  
  
  RESULTS
  The mean PF ADA level was significantly higher in the tuberculous pleural group than in non-tuberculous pleural patients (63.3 ± 29 IU/l vs. 19 ± 31 IU/l, P < 0.001). There was a significant correlation between PF ADA levels and age: for patients aged ⩾45 years, the ROC curve for ADA had an area under the curve of 0.91. An ADA level of 29 IU/l resulted in a sensitivity of 88.6% and specificity of 91.5%.
  
  
  CONCLUSIONS
  There is a significant negative correlation between PF ADA level and age. The use of a lower ADA cut-off reduces the number of false-negative results.
authors.affiliation: Department of Thoracic Surgery, Hospital Santa Marcelina, São Paulo, Brazil.
authors.forename: F C
authors.initials: FC
authors.lastname: Abrao
authors.affiliation: Department of Thoracic Surgery, Hospital Santa Marcelina, São Paulo, Brazil.
authors.forename: I R L Bruno
authors.initials: IR
authors.lastname: de Abreu
authors.forename: D H
authors.initials: DH
authors.lastname: Miyake
authors.affiliation: Department of Thoracic Surgery, Hospital Santa Marcelina, São Paulo, Brazil.
authors.forename: D H
authors.initials: DH
authors.lastname: Miyaki
authors.affiliation: Department of Pneumology, Instituto Clemente Ferreira, São Paulo, Brazil.
authors.forename: M A M
authors.initials: MA
authors.lastname: Busico
authors.affiliation: Department of Surgery, Hospital Sao Jose, University of São Paulo, São Paulo, São Paulo, Brazil.
authors.forename: R N
authors.initials: RN
authors.lastname: Younes
mesh_terms: D000243:Adenosine Deaminase / Q000378:metabolism*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D001706:Biopsy; D001938:Brazil / Q000453:epidemiology; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000175:diagnosis* / Q000201:enzymology / Q000453:epidemiology; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014396:Tuberculosis, Pleural / Q000175:diagnosis* / Q000201:enzymology / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000243:Adenosine Deaminase