title: Induced sputum for the diagnosis of pulmonary tuberculosis: Is it useful in clinical practice?
abstract: BACKGROUND
  Diagnosing pulmonary tuberculosis (PTB) is challenging in patients who are unable to spontaneously expectorate. Published evidence suggests that induced sputum (IS) is the least invasive and most cost-effective method of diagnosis, and should be used before fibre-optic bronchoscopy (FOB).
  
  
  METHODS
  The medical records of 337 adults treated for PTB in northern Alberta between 1997 and 2007 were reviewed to determine whether local practice patterns reflect the evidence. Microbiological data were collected from the Provincial Laboratory for Public Health. Demographic information was collected from the patients' charts.
  
  
  RESULTS
  A total of 8.5% (26 of 307) of PTB patients had IS collected, whereas 35.8% (110 of 307) underwent FOB. Among FOB patients, 56.4% (62 of 110) had no sputum sent before the procedure and 29% (18 of 62) of these patients were smear positive. Only five patients referred for FOB had IS sent previously. There were no demographic factors predictive of IS use, whereas being an inpatient at a teaching facility or having a nodule or mass on chest x-ray was predictive of FOB referral. Because so few IS samples were available, not all patients had spontaneously expectorated sputum, IS and FOB tests performed; thus, the calculated yields were not comparable with one another.
  
  
  CONCLUSIONS
  Despite published evidence recommending IS collection before FOB referral in suspected PTB patients, clinicians in our health region appeared to prefer early FOB over IS by a large margin. This practice pattern is less cost effective and exposes patients and health care workers to greater risk. Further research is needed to identify the reasons for the underuse of sputum induction.
authors.affiliation: Division of Pulmonary Medicine, University of Alberta, Edmonton, Alberta. sjo@ualberta.ca
authors.forename: Sharla-Rae
authors.initials: SR
authors.lastname: Olsen
authors.forename: Richard
authors.initials: R
authors.lastname: Long
authors.forename: Gregory
authors.initials: G
authors.lastname: Tyrrell
authors.forename: Dennis
authors.initials: D
authors.lastname: Kunimoto
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000416:Alberta; D001999:Bronchoscopy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D013183:Sputum / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*; D055815:Young Adult
references.citation: Am Rev Respir Dis. 1990 Sep;142(3):505-7
references.pmid: 2389901
references.citation: Int J Tuberc Lung Dis. 2009 Jan;13(1):99-104
references.pmid: 19105886
references.citation: Am J Respir Crit Care Med. 2007 Jan 1;175(1):80-6
references.pmid: 17053204
references.citation: Indian J Chest Dis Allied Sci. 2008 Jan-Mar;50(1):67-78
references.pmid: 18610691
references.citation: Clin Infect Dis. 2004 May 15;38(10):1504-5
references.pmid: 15156494
references.citation: Am Rev Respir Dis. 1982 May;125(5):559-62
references.pmid: 7081816
references.citation: Clin Infect Dis. 2007 Jun 1;44(11):1415-20
references.pmid: 17479935
references.citation: Int J Tuberc Lung Dis. 2003 Nov;7(11):1015-26
references.pmid: 14598959
references.citation: Mymensingh Med J. 2008 Jul;17(2):115-23
references.pmid: 18626443
references.citation: Am J Respir Crit Care Med. 1995 Nov;152(5 Pt 1):1570-4
references.pmid: 7582296