An effective strategy for diagnosing occupational asthma: use of induced sputum.
Monitoring airway inflammation by means of induced sputum cell counts seems to improve the management of asthma. We sought to assess whether such monitoring at the end of periods at and away from work combined with the monitoring of PEF could improve the diagnosis of occupational asthma. We enrolled subjects suspected of having occupational asthma. Serial monitoring of PEF was performed during 2 weeks at and away from work. At the end of each period, induced sputum was collected. Specific inhalation challenge was subsequently performed. PEF graphs were interpreted visually by five independent observers. Forty-nine subjects, including 23 with positive specific inhalation challenge, completed the study. The addition of sputum cell counts to the monitoring of PEF increased the specificity of this test, respectively, by 18 (range [r] 13.7-25.5) or 26.8% (r 24.8-30.4) depending if an increase of sputum eosinophils greater than 1 or 2% when at work was considered as significant. The sensitivity increased by 8.2% (r 4.1-13.4) or decreased by 12.3% (r 3.1-24.1) depending on the cutoff value in sputum eosinophils chosen (greater than 1 or 2%, respectively). The addition of sputum cell counts to PEF monitoring is useful to improve the diagnosis of occupational asthma.
Department of Chest Medicine, Sacré-Coeur Hospital, 5400 West Gouin, Montreal, Quebec, H4J 1C5 Canada.
Frédéric
F
Girard
Simone
S
Chaboillez
André
A
Cartier
Johanne
J
Côté
Frederick E
FE
Hargreave
Manon
M
Labrecque
Jean-Luc
JL
Malo
Susan M
SM
Tarlo
Catherine
C
Lemière
D000328:Adult; D001249:Asthma / Q000175:diagnosis*; D001985:Bronchial Provocation Tests; D018592:Cross-Over Studies; D004804:Eosinophils / Q000166:cytology; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D016210:Methacholine Chloride; D009784:Occupational Diseases / Q000175:diagnosis*; D010366:Peak Expiratory Flow Rate; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013183:Sputum / Q000166:cytology*; D017132:Workplace
D016210:Methacholine Chloride