Comparison of sputum induction with fiber-optic bronchoscopy in the diagnosis of tuberculosis

Am J Respir Crit Care Med. 1995 Nov;152(5 Pt 1):1570-4. doi: 10.1164/ajrccm.152.5.7582296.


Microbiologic confirmation of pulmonary tuberculosis among patients whose sputum smear is negative is increasingly important because of greater incidence among immunocompromised hosts and emergence of drug-resistant strains. We prospectively compared sputum induction to fiber-optic bronchoscopy in the diagnosis of such patients. Consecutive patients referred for investigation of possible active pulmonary tuberculosis underwent sputum induction with hypertonic saline delivered by an ultrasonic nebulizer between 2 and 48 h before transnasal fiber-optic bronchoscopy. All specimens were examined for acid-fast bacilli with fluorescent microscopy and cultured for mycobacteria. Clinical information was abstracted from patient records, and X-rays were reviewed by two blinded readers. Among 101 participants, sputum induction was well-tolerated without complications and provided adequate samples in 93. Sensitivity of direct acid-fast bacilli smear of specimens from both techniques was low. Sensitivity and negative predictive value of culture from bronchoscopy specimens was 73% and 91% compared with 87% and 96%, respectively, for sputum induction when a specimen was obtained. Direct costs for bronchoscopy totaled Canadian $187.60 compared with Canadian $22.22 for sputum induction. Sputum induction was well-tolerated, low-cost, and provided the same, if not better, diagnostic yield compared with bronchoscopy in the diagnosis of smear-negative pulmonary tuberculosis.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Bronchoscopy* / economics
  • Bronchoscopy* / methods
  • Canada
  • Costs and Cost Analysis
  • Female
  • Fiber Optic Technology
  • Humans
  • Male
  • Mycobacterium tuberculosis / isolation & purification
  • Optical Fibers
  • Prospective Studies
  • Saline Solution, Hypertonic / administration & dosage
  • Sensitivity and Specificity
  • Sputum / drug effects
  • Sputum / microbiology*
  • Tuberculosis, Pulmonary / diagnosis*
  • Tuberculosis, Pulmonary / economics


  • Saline Solution, Hypertonic