title: Diagnostic yield of sputum, induced sputum, and bronchoscopy after radiologic tuberculosis screening.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Pneumology, Kantonsspital St. Gallen, CH-9007 St. Gallen, Switzerland. otto.schoch@kssg.ch
authors.forename: Otto D
authors.initials: OD
authors.lastname: Schoch
authors.forename: Philippe
authors.initials: P
authors.lastname: Rieder
authors.forename: Claudia
authors.initials: C
authors.lastname: Tueller
authors.forename: Ekkehardt
authors.initials: E
authors.lastname: Altpeter
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Zellweger
authors.forename: Hans L
authors.initials: HL
authors.lastname: Rieder
authors.forename: Martin
authors.initials: M
authors.lastname: Krause
authors.forename: Robert
authors.initials: R
authors.lastname: Thurnheer
mesh_terms: D000293:Adolescent; D000328:Adult; D001980:Bronchi / Q000002:abnormalities; D001999:Bronchoscopy / Q000379:methods*; D018929:Cell Culture Techniques; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D011859:Radiography; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000000981:diagnostic imaging