Tistamine and methacholine inhalation challenge are used extensively to determine bronchial reactivity and the likelihood of asthma in patients in whom the diagnosis is not obvious. Critical analyses, however, have shown that, as with all laboratory tests, there is overlap of results for normal and abnormal subjects. This overlap forces the physician to use decision analysis in the interpretation of test results; the analysis may be done subconsciously on the basis of experience and intuition or by a more formal process such as Bayesian analysis. A formal analysis has been published for histamine provocation by Popa and Singleton. To our knowledge an analysis for methacholine challenge has not been presented, but the recently published data of Casale and associates provide a basis for such an analysis.
The purpose of this report is to use the data of Casale et al as a model to demonstrate how simple decision analysis theory can be applied to the interpretation of a bronchial provocation test. The relevance and limitations of applying this model to other data bases will be discussed. viagra jelly online