title: Use of bronchoalveolar lavage enzyme-linked immunospot for diagnosis of smear-negative pulmonary tuberculosis.
abstract: OBJECTIVE
  To compare the diagnostic validity of blood enzyme-linked immunospot assay (ELISpot), broncho-alveolar lavage (BAL) ELISpot and the tuberculin skin test (TST) in patients with pulmonary smear-negative tuberculosis (TB) in a country with high TB prevalence.
  
  
  METHODS
  In a  prospective, hospital-based study, 107 patients with suspected TB were tested simultaneously using blood and BAL ELISpot and TST.
  
  
  RESULTS
  Of 102 patients with active pulmonary TB, 36 (35.3%) were diagnosed with TB, while 66/102 (64.7%) had a non-TB diagnosis. The sensitivity and specificity  for ELISpot on mononuclear cells from BAL fluid was respectively 94.4% (95%CI 81.9-98.5) and 78.1% (95%CI 66.6-86.5). The specificity of BAL ELISpot was significantly higher than that of blood ELISpot (P = 0.011). Compared with blood ELISpot and TST, BAL ELISpot was not  significantly influenced by previous history of TB (OR 2.05, P > 0.05) or household contact with a patient with active TB (OR 2.41, P > 0.05).
  
  
  CONCLUSIONS
  ELISpot on BAL appears to be a more rapid and sensitive supplementary test than on blood for the diagnosis of active  TB patients with a negative sputum smear in a developing country setting with high TB prevalence and access to bronchoscopy and ELISpot assay. However, the test's utility was limited by its moderate specificity.
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Guangxi Medical University, Nanning, China.
authors.forename: H
authors.initials: H
authors.lastname: Li
authors.forename: L
authors.initials: L
authors.lastname: Yang
authors.forename: C-Y
authors.initials: CY
authors.lastname: Zheng
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: A S
authors.initials: AS
authors.lastname: Abdullah
mesh_terms: D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology*; D001999:Bronchoscopy; D016009:Chi-Square Distribution; D002681:China / Q000453:epidemiology; D016358:Contact Tracing; D003906:Developing Countries; D058501:Enzyme-Linked Immunospot Assay; D006297:Health Services Accessibility; D006798:Housing; D006801:Humans; D059425:Interferon-gamma Release Tests; D016015:Logistic Models; D015999:Multivariate Analysis; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D016017:Odds Ratio; D011237:Predictive Value of Tests; D015995:Prevalence; D011446:Prospective Studies; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology*; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology