The methacholine challenge test is a method of assessing airway responsiveness. The purpose of a methacholine challenge test is to determine the amount of airway irritability in a patient. You will be asked to inhale a mist that contains different concentrations of methacholine. The mist is produced by a device called a nebulizer and inhaled through a mouthpiece. Results of pulmonary function tests performed before and after inhalations are used to quantitate response. The test usually takes about an hour.
Your healthcare provider will provide you with a list of medications that should be withheld on the day of the test, which may affect the results of the methacholine challenge test.