Use of the specific challenge in the diagnosis of occupational asthma: a 'gold standard' test or a test not used in current practice of occupational asthma?

Purpose of review This review, an assessment of the role of inhalational challenge testing in the diagnosis of occupational asthma, focuses on the difficulties associated with making the correct diagnosis of occupational asthma. This report contrasts the apparent discrepancy between the clinical diagnosis and the diagnosis made by inhalational challenge testing, the `gold standard'. This disparity has been pointed out by a number of authors, yet this approach to making the diagnosis of this illness continues. Recent findings Because of the disparity between the clinical mode for diagnosis and using specific challenge testing for diagnosis, awarding compensation to a worker based on the clinical diagnosis of occupational asthma, or using this clinical approach to identify the incidence or prevalence of occupational asthma in a population, is suspect. In the absence of specific inhalational challenge, physicians have attempted to understand changes in flow rates over time through the use of serial peakflow assessments, a relatively cost-effective way to sort out the diagnosis. Yet, there is an increasing body of knowledge which presents information casting concern on the adequacy of these measurements. In addition, recent data suggest that chest physicians, occupational medicine physicians, and allergists most often make a diagnosis of occupational asthma by usual clinical methodology, which is a routine part of their hospital's pulmonary function laboratory. Summary The apparent lack of training in the approach to specific inhalation challenge testing in fellowship programs, the relatively few specialized centers, and the apparent lack of recognition by many physicians who are presented with a patient with suspected occupational asthma means that the use of routine methods to make the clinical diagnosis may often be incorrect, making it unlikely that this approach to the diagnosis of occupational asthma will change in the near future.