Provocation (Trigger) Tests
A provocation test (proh-voh-KA-shun) is a type of lung test that tells how sensitive your lungs are. These types of tests may also be called challenge or trigger tests. The most common types of provocation tests are:
- Irritant challenge
- Exercise challenge
- Methacholine (meth-uh-koh-leen) challenge
Your doctor may choose to do a provocation test for the following reasons:
- To confirm you have asthma
- To rule out asthma if other tests or exams did not give a clear diagnosis
With each dose of irritant, your doctor will have you take a spirometry test before and after to see if or by how much your lung function changes.
With an irritant challenge, your doctor will expose you to a specific asthma trigger to see if your airways react. These might include chemicals, perfume or smoke. After you are exposed to the trigger, you will take a breathing test to see how you respond. This test helps your doctor confirm possible asthma triggers.
For some, exercise triggers asthma symptoms. This is known as exercise-induced bronchoconstriction (EIB).
During an exercise test, you run on a treadmill while your oxygen and heart rate are monitored. This will help your doctor determine if exercise triggers your symptoms.
Methacholine is a type of drug that will make your airways tighten up at a lower dose if you have asthma or at a higher dose if you do not have asthma. During this test, your doctor will have you breathe in increasing doses of methacholine. Then they will do a spirometry test to see if your lung function changes.
If your lungs do not react to lower doses of methacholine, you may have another condition that has similar symptoms to asthma. Some conditions that have similar symptoms are:
- Upper airway obstruction
- Heart failure
- Vocal cord dysfunction
- Bronchopulmonary dysplasia
- Cystic fibrosis
- Enlarged lymph nodes
- Lung cancer (tumors)
- Viral infections
- Sinus infections
- Chronic obstructive pulmonary disease (emphysema or chronic bronchitis)
If you are on a treatment plan for asthma, but the treatment isn't working, talk to your doctor. The site isitasthma.com has a conversation guide you can fill out and take to your doctor to see if a methacholine challenge is right for you.