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Baylor Health Care System > Physicians & Locations > Dallas > Specialties & Services > Asthma Care > Methacholine Challenge Test (bronchial provocation)

Methacholine Challenge Test (bronchial provocation)  

The bronchial provocation test evaluates how sensitive the airways in your lungs are and a spray called methacholine may be inhaled. A spirometry breathing test is done before and after you inhale the spray. Spirometry can show how much air you can breathe in and out. It also shows how fast you can breathe in and out. The spirometry results are compared before and after you inhale the spray to see what changes there are in your breathing.

Methacholine challenge test: This lung function test for asthma is more commonly used in adults than in children. It might be performed if your symptoms and screening spirometry do not clearly or convincingly establish a diagnosis in asthma. Methacholine is an agent that, when inhaled, causes the airways to spasm (contract involuntarily) and narrow if asthma is present. During this test, you inhale increasing amounts of methacholine aerosol mist before and after spirometry. The methacholine test is considered positive, meaning asthma is present, if the lung function drops by at least 20%. A bronchodilator is always given at the end of the test to reverse the effects of the methacholine.