Bronchoprovocation testing.

Bronchoprovocation testing has been performed for more than 50 years. Challenge testing with nonselective agents has been used widely for the assessment of airflow limitation in patients, and has been used in the research setting to better characterize the pathophysiology of bronchial responsiveness. Based on this large body of literature, detailed guidelines are now available to allow for standardization of testing methodology. Such standardization is critical to achieve safe, accurate, and reproducible test results that may be interpreted meaningfully. Currently, bronchoprovocation testing with direct-acting stimuli such as methacholine is used most frequently in the clinical arena, but, in recent years, considerable interest has been developing in the use of indirect stimuli. (57) It now is recognized that bronchial hyperresponsiveness to indirect stimuli (e.g., exercise, cold air, and AMP) is highly specific for asthma and may have greater clinical relevance than does responsiveness to direct stimuli. (8) As a result, testing with indirect agents may become employed more widely in the future.