Occasional reviews Methodology of bronchial responsiveness

Recommendations for the standardisation of bronchial challenge were made in 1985, and updated in 1993. However, neither document recommended a single protocol or even criteria that would recommend the adoption of a particular method. Even the terminology lacks uniformity, bronchial responsiveness being used in this review in the hope that it oVends the fewest number of readers. Distinction has been made, but not consistently, between (hyper)responsiveness as a general term, (hyper)sensitivity as a leftward shift in the dose-response curve, and (hyper)reactivity as an increase in the dose-response slope. “Airway” and “bronchial” have been used interchangeably. The prefix “hyper” has connotations of excessive, implying a bimodal distribution in the population. Although this has not been substantiated, the acronyms BHR (bronchial hyperresponsiveness) and AHR (airway hyperresponsiveness) are well established, the former being adopted in this article. A review of the methodology of BHR might be expected to cover all aspects of bronchial challenge, but one short article cannot provide this. Rather than reproduce recommendations which were comprehensive on most details, this paper emphasises variations in protocol that lead to results from diVerent studies being non-comparable, explains how diVerent methods of summary have arisen, and discusses the implications of these.