Diagnostic yield of sputum, induced sputum, and bronchoscopy after radiologic tuberculosis screening

Am J Respir Crit Care Med. 2007 Jan 1;175(1):80-6. doi: 10.1164/rccm.200608-1092OC. Epub 2006 Oct 19.


Rationale: To assess feasibility and yield of diagnostic procedures after active case finding for tuberculosis with radiologic screening at the three main entry points for asylum seekers to Switzerland.

Method: Prospective multicenter study on the value of symptoms, spontaneous and induced sputum, and bronchoscopy for the confirmation of tuberculosis in radiologically selected cases.

Results: Among 101 asylum seekers examined, spontaneous sputum was collected "on the spot" in 83 and yielded 7 (54%) of 13 smear-positive and 13 (39%) of 33 culture-positive cases. Morning sputum, collected in 84, yielded 8 (62%) and 16 (49%), and the two spontaneous sputa combined 9 (69%) and 20 (61%), respectively. Two additional induced sputa, collected in 91 persons, yielded no additional smear-positive, but yielded seven culture-positive cases (yield, 82%). Bronchoscopy, performed in 87 of 92 sputum smear-negative cases, yielded four additional smear-positive and six culture-positive cases. Culture confirmation was independently and significantly predicted by obtaining a specimen using bronchoscopy (adjusted odds ratio, 11.0; 95% confidence interval, 1.9-62) and a prior decision to treat (adjusted odds ratio, 3.0; confidence interval, 1.1-8.1).

Conclusion: Radiographic anomalies compatible with tuberculosis found during screening are a poor guide to initiation of treatment. Respiratory and systemic symptoms correlated weakly with culture confirmation of tuberculosis. All radiologically selected cases must be examined with on-the-spot and early-morning sputum, regardless of symptoms. If both specimens are smear negative, the yield is increased by bronchoscopy and, to a lesser extent, by two samples of induced sputum. The examination of any single specimen has a low yield of 36 to 63% and is insufficient to exclude active tuberculosis.

Publication types

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

MeSH terms

  • Adolescent
  • Adult
  • Bronchi / abnormalities
  • Bronchoscopy / methods*
  • Cell Culture Techniques
  • Diagnosis, Differential
  • Female
  • Humans
  • Male
  • Mass Screening
  • Mycobacterium tuberculosis / isolation & purification*
  • Radiography
  • Sensitivity and Specificity
  • Sputum / microbiology*
  • Tuberculosis, Pulmonary / diagnosis*
  • Tuberculosis, Pulmonary / diagnostic imaging