Asthma-like symptoms induced by the methacholine challenge test: do they predict a negative-to-positive switch in the test result?—case report

Abraham B. Bohadana, Ariel Rokach, Pascal Wild, Gabriel Izbicki


The methacholine challenge test (MCT) is primarily indicated to help determine if current respiratory symptoms may be due to asthma or not (1,2). A positive test is generally defined as the provocative concentration (or dose) of methacholine causing a 20% fall in forced expiratory volume in one second (PC20FEV1) without consideration of the symptoms that may occur during the test, such as dyspnoea, cough, chest tightness and wheezing (2).