Also known as the bronchoprovocation test, this diagnostic tool is used to determine how reactive a patient’s lungs are when exposed to small doses of methacholine. During the test, this dose is gradually increased in order to evaluate how the patient’s breathing ability responds. A dip of 20 percent or more indicates a reactive airway that may be the result of asthma. At the Pulmonary & Sleep Center of the Valley, we use the methacholine challenge as one tool in diagnosing disorders such as asthma. Once we diagnose you with a disorder we can then implement treatments designed to help you breathe better and live with or overcome your condition.