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This Article Full Text Full Text (PDF) All Versions of this Article: 34/3/574    most recent 09031936.00150108v1 Alert me when this article is cited Alert me if a correction is posted Permissions Request Permissions Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Park, D. Articles by Burge, P. S. PubMed PubMed Citation Articles by Park, D. Articles by Burge, P. S.

Serial PEF measurement is superior to cross-shift change in diagnosing occupational asthma

¹ Occupational Lung Disease Unit, Birmingham Heartlands Hospital, and ² Dept of Occupational and Environmental Medicine, University of Birmingham, Edgbaston, Birmingham, UK.

CORRESPONDENCE: P. S. Burge, Occupational Lung Disease Unit, Birmingham Heartlands Hospital, Bordesley Green East, Birmingham, B9 5SS, UK. E-mail: sherwood.burge{at}heartofengland.nhs.uk

Keywords: Oasys-2, occupational asthma, peak expiratory flow, pulmonary function testing

Received: October 23, 2008
Accepted March 9, 2009

Cross-shift measurements of peak expiratory flow (PEF) are commonly employed in the diagnosis of occupational asthma, although evidence for this approach is lacking. The current paper presents an evaluation of the technique.

Mean changes in PEF across morning/day shifts were compared between workers with occupational asthma, confirmed using specific challenge testing, and non-working asthmatics. Individuals were divided into a development set, used to identify the optimum cross-shift change for diagnosing occupational asthma, and an evaluation set, used to test the sensitivity and specificity of this value. Comparative analysis of serial PEF records was performed using the Oasys-2 computerised system.

A cross-shift decrease in PEF of 5 L·min^–1 achieved acceptable specificity in the development set. Applied to the evaluation set, this cut-off had a specificity of 90.9% and a sensitivity of 50%. Sensitivity could not be improved without unacceptable compromise to specificity. Analysis of serial PEF records using linear discriminant analysis identified occupational asthma with a sensitivity of 83.3% and a specificity of 90.9%. Serial analysis using mean work/rest day PEF comparison had a sensitivity of 66.7% and a specificity of 100%.

Cross-shift changes in PEF in morning/day-shift workers have poor sensitivity in diagnosing occupational asthma, and are inferior to serial techniques.