title: Yield of smear, culture and amplification tests from repeated sputum induction for the diagnosis of pulmonary tuberculosis.
abstract: OBJECTIVE
  To assess the yield of repeated sputum induction for the diagnosis of active tuberculosis in patients who do not produce spontaneous sputum, or with smear-negative spontaneous samples.
  
  
  METHODS
  Induced sputum was examined with fluorescent microscopy, two amplification methods (PCR Amplicor MTB, and MTD2), and cultured for mycobacteria using liquid (Bactec 12B) and Lowenstein-Jensen media. Bronchoscopy and collection of other specimens were performed at the discretion of the treating physician.
  
  
  RESULTS
  A total of 1115 sputum inductions performed in 500 patients without adverse events yielded an adequate specimen in 1113 (99.8%), and microbiological confirmation in 43 of 44 (98%) culture-positive active TB cases. Yield increased with repeated sputum induction. The cumulative yield for acid-fast bacilli smear and mycobacterial culture was 64% and 70% respectively for one, 81% and 91% for two, 91% and 99% for three, and 98% and 100% for four induced samples. Yield of PCR also increased with the greater number of induced samples tested.
  
  
  CONCLUSIONS
  Repeated sputum induction could considerably improve diagnostic accuracy for pulmonary TB.
authors.affiliation: Montreal Chest Institute, McGill University, PQ, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Al Zahrani
authors.forename: H
authors.initials: H
authors.lastname: Al Jahdali
authors.forename: L
authors.initials: L
authors.lastname: Poirier
authors.forename: P
authors.initials: P
authors.lastname: René
authors.forename: D
authors.initials: D
authors.lastname: Menzies
mesh_terms: D000704:Analysis of Variance; D001999:Bronchoscopy; D006801:Humans; D008856:Microscopy, Fluorescence; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification*; D021141:Nucleic Acid Amplification Techniques; D011446:Prospective Studies; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage; D012680:Sensitivity and Specificity; D013048:Specimen Handling; D013183:Sputum / Q000382:microbiology*; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000235:genetics*
chemical_list: D012462:Saline Solution, Hypertonic