Spirometry Test: What It Is and Who Should Get One

A spirometry test gives a number for something you cannot feel: how well air moves through your lungs. Coughing, breathlessness and a chest that feels tight can have many causes, and this test helps a doctor sort them out. It is quick, it usually happens in an office or clinic, and most people finish it in one visit. Here is what the test measures, what the appointment involves and who the sources say should ask about it.

What a spirometry test is

The Lung Health Foundation says spirometry is the most reliable way to test your lungs for chronic obstructive pulmonary disease (COPD) and asthma. HealthLinkBC calls it the most common lung function test. Your provider may also call it a pulmonary function test or a lung function test.

What it measures

The Lung Health Foundation says the machine measures how much air you can blow out of your lungs and how fast you can blow it out. Two readings come up often. Forced vital capacity (FVC) is the largest amount of air you can blow out after your biggest breath in. Forced expiratory volume (FEV1) is the amount you can blow out in the first second. Your provider compares your numbers with the range expected for healthy lungs. HealthLinkBC says abnormal results may point to obstructive conditions, which narrow the airways, or restrictive conditions, which limit how far the lungs expand.

What happens at the appointment

The Lung Health Foundation says you breathe through a mouthpiece while wearing a nose clip. You take a full breath in, then blow out as hard and as fast as you can until your lungs feel empty. You repeat the blow at least three times so the results are accurate. Wikipedia describes the target for each blow as a maximum effort exhale of at least 6 seconds, so expect your technician to coach you to keep going.

HealthLinkBC says most results are ready right away. It also says that for a healthy person there is little or no risk in taking these tests. If you have a serious heart or lung condition, it advises talking to your doctor about risks first.

Getting ready

HealthLinkBC says not to smoke or do intense exercise for 6 hours before the test. It also suggests avoiding a heavy meal, wearing loose clothing and telling your doctor about any lung medicines you take, since some may need to be paused. Instructions can differ between clinics, so follow what your booking tells you and ask if anything is unclear.

Who should ask about one

The Lung Health Foundation says smokers and former smokers are at a higher risk of developing COPD, and it calls smoking the number one cause of COPD. It calls spirometry the gold standard way to diagnose COPD and says a chest X-ray should not be used to confirm it. It also advises anyone with a lung health concern who has never had the test to talk to a healthcare provider about spirometry.

Symptoms are a reason to raise it. A long-lasting cough, breathlessness or wheezing is worth a conversation, and our guide to when a smoker’s cough needs a doctor covers the warning signs. The COPD symptoms page lists what to look for, and the pages on emphysema and chronic bronchitis describe the two conditions that fall under COPD. For a wider picture of what smoke does to the airways, see smoker’s lungs.

How to get one in Canada

The Lung Health Foundation says the test can often be done in your healthcare provider’s office or in a nearby clinic, and that your provider is the person to ask. The sources we read do not describe a booking process, wait times or costs, and these can differ by province. Your family doctor, a nurse practitioner or the 811 health line can tell you what is available where you live.

If you smoke and are thinking about quitting, tell your provider. Many provinces fund help to quit, and our page on what is free for you explains the options.

What we could not confirm

• Whether pharmacies or community programs offer spirometry in your province. None of the sources we read say so.
• Wait times, costs and referral rules, which none of the sources describe.
• Exact fasting or smoking cut-off times that apply to every clinic. The sources we read give different lead times, so check with the clinic.
• How the Canadian Thoracic Society guidance describes the test. We could not open its guideline pages.

This page is general information. It is not personal medical advice, so talk to a doctor, pharmacist or 811 about your own symptoms.