Pulmonary Function Lab

Respiratory therapists work closely with our team of respirologists, who interpret your test results to help diagnose and treat your condition.

Please arrive at the lab 15 minutes before your appointment to check in.

Pulmonary function tests

Pulmonary function tests (PFTs) measure how well your lungs work. Depending on your needs, you may have one test or a combination. PFTs help diagnose conditions such as:

• Asthma
• Chronic obstructive pulmonary disease (COPD)
• Pulmonary fibrosis

Spirometry

Spirometry is the most common pulmonary function test. It measures how much air you can inhale and exhale.

During the test, you breathe into a mouthpiece connected to a spirometer, a device that measures the movement of air as you breathe in and out. In some cases, your respiratory therapist may ask you to inhale medication that opens your airways as part of the test.

Wear comfortable clothing and follow any instructions you're given about taking your respiratory medication before the test.

You can return to your regular activities after your test.

Lung plethysmography

Lung plethysmography measures how much air is in your lungs while you inhale.

During the test, you sit inside a clear plastic box. Your respiratory therapist places a clip on your nose so you can breathe only through your mouth, then closes the box. You breathe into a mouthpiece connected to a machine called a plethysmograph, which measures pressure changes in the box to determine your lung volume.

Wear comfortable clothing and follow any instructions you're given about taking your respiratory medication before the test.

You can return to your regular activities after your test.

Lung diffusion

Lung diffusion measures how well your lungs move oxygen into your blood.

During the test, you breathe through a mouthpiece connected to a machine that delivers air mixed with a small amount of carbon dioxide and either methane or helium.

Your respiratory therapist will tell you how to breathe and when to hold your breath.

Wear comfortable clothing and follow any instructions you're given about taking your respiratory medication before the test.

You can return to your regular activities after your test.

Methacholine challenge test

This test shows health-care providers how your lungs react to methacholine, a medication that narrows the airways. A strong reaction may indicate asthma.

First, a respiratory therapist gives you a spirometry test to check your breathing.

Then you inhale a dose of methacholine through a nebulizer, a small device that turns the liquid methacholine into a mist you breathe in through a mouthpiece.

After each dose, you have another spirometry test. How many rounds you need depends on how your breathing responds.

Once the test is complete, your respiratory therapist gives you medication that opens up your airways and confirms your lung function has returned to normal.

Wear comfortable clothing and follow any instructions you're given about taking your respiratory medication before the test.

Cardio-pulmonary exercise test

This test shows health-care providers how your heart and lungs respond to exercise. It may be recommended if you experience shortness of breath.

You may have a spirometry test or other pulmonary function tests before you begin.

During the test, you ride a stationary bike in the lab while we monitor your breathing, oxygen levels and heart activity.

This test can help diagnose:

• Exercise-induced asthma
• Pulmonary hypertension
• Cardiovascular disease

Please do not smoke on the day of your test, and tell your respiratory therapist if you have any of the following:

• Surgery within the last four weeks
• History of aortic or brain aneurysms
• Episodes of coughing up blood
• Recent stroke
• An infectious disease, such as COVID-19 or tuberculosis
• Heart issues, such as angina or uncontrolled blood pressure

Follow any instructions you're given about taking your respiratory medication before the test.

You can return to your regular activities after your test.

What to bring

• Health (OHIP) card or valid health-care coverage
• Comfortable clothing
• Running shoes, if you are having a cardio-pulmonary exercise test

How to access our services

You need a referral from a health-care provider to be seen at the lab. See our referral criteria for more information.