Bronchial challenge testing

Airways hyperresponsiveness can occur as solitary evidence of airways dysfunction. Because hyperresponsiveness is associated with the presence and severity of disease, it is important to measure and quantitate airways responsiveness. The most useful challenge procedure appears to be the methacholine challenge, not so much because it offers the best specificity of the challenge procedures but because it has been characterized well. Although the procedures are simple, interpretation of the results is problematic. It is important to remember that the key features of asthma are the periodicity and lability of signs and symptoms. Assessment of airways responsiveness is a significant addition to the armamentarium of the modern diagnosis and treatment of asthma.