← All guides · Heart, lungs and nerves tests

Methacholine challenge test

methacholine test · bronchial challenge test · bronchial provocation test · airway hyperresponsiveness test

You breathe in a substance in small, slowly rising doses and do a breathing test, called spirometry, after each one. This checks how sensitive your airways are.

When asthma is suspected but a regular spirometry is normal.

⏱ Duration: usually 1 to 2 hours; the result is given right away

Be sure to tell your doctor

All inhalers and medicines. Some must be stopped ahead of time, but only as your doctor says
If you are pregnant or breastfeeding
If you had a heart attack, a stroke, or a recent cold
If you have high blood pressure

How to prepare

Medicines. Many inhalers and allergy pills are stopped for different lengths of time before the test. Your doctor will give you the plan. Do not stop anything on your own.
Coffee. On the day of the test, you usually cannot have coffee, tea, cola, or chocolate. Check with the clinic.
Smoking and exercise. Do not smoke or exercise on the day of the test.
Your health. If you catch a cold, call the clinic. The test is usually moved.

What to bring

Your referral
A list of your medicines
Your rescue inhaler

How it goes

First, you do a regular spirometry test
You breathe in a small dose of the substance through a nebulizer
After a couple of minutes, you do spirometry again
The dose is slowly increased and the steps repeated
The test stops when your readings drop or the full program is done
At the end, you get an inhaler to bring your breathing back to normal

What you'll feel

You may cough or feel slight tightness in your chest
Sometimes wheezing. The doctor is right there and will relieve it with an inhaler
Blowing out so many times can be tiring

Afterwards

You can leave when your breathing is back to where it started
You are usually told the result right away
You can go back to your medicines. Ask your doctor

Contact a doctor straight away if

Cough or shortness of breath comes back at home and the inhaler does not help: call emergency services
Wheezing in the chest and trouble speaking

Common questions

Is it dangerous?

The test is done under a doctor's watch, with medicines ready. Strong reactions are rare.

Why stop my inhalers?

Otherwise the test may give a wrong result. Only your doctor decides what to stop and for how long.