Spirometry

What is spirometry?

Spirometry (pronounced “spy-rom-uh-tree”) is a common type of pulmonary function test. Another name for a pulmonary function test is a lung function test. A spirometry test measures the flow of air through your lungs and estimates the amount of air in your lungs. It also tells your healthcare provider how strong your lungs are and how well you breathe.

Spirometry is safe. Healthcare providers commonly order it to evaluate lung function.

Why is spirometry performed?

Spirometry determines if your lungs are functioning at their expected levels. It also helps to diagnose lung and airway diseases, including:

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

Spirometry can also:

• Determine your lung capacity.
• Measure changes over time that occur as a result of chronic lung diseases.
• Identify early changes in your lung function and, in some cases, help guide treatment.
• Detect narrowing of your airways.
• Decide how likely it is that inhaled medications may help with your symptoms.
• Show whether exposure to certain substances has altered your lung function.
• Estimate your risk of respiratory complications before undergoing surgery.

When would spirometry be needed?

Your healthcare provider may order spirometry if you have symptoms of lung or airway conditions. Some symptoms in which your healthcare provider may order spirometry include:

• Chest tightness, pain or pressure.
• Coughing, especially coughing with mucus.
• Difficulty taking a deep breath.
• Shortness of breath (dyspnea).
• Wheezing.

Who performs spirometry?

Your respiratory therapist, nurse, general practitioner (GP) or pulmonologist may perform spirometry.

Is a spirometer good for my lungs?

A spirometer is a medical device that measures your airflow. It doesn’t help your lungs, but it helps your healthcare provider determine if there’s a problem with your breathing.

How does spirometry work?

Spirometry uses a machine called a spirometer. A spirometer is a medical device that consists of a mouthpiece that connects to a computerized machine that measures your airflow.

How do I prepare for a spirometry test?

Before your test, your healthcare provider may ask you to:

• Stop taking your breathing medications for a short period.
• Wear loose, comfortable clothing that doesn’t squeeze your chest.
• Refrain from eating a large meal at least two hours before the test.
• Avoid any heavy exercise at least 30 minutes before the test.

These precautions help ensure that your spirometry results are more accurate.

How is a spirometry test performed?

Your healthcare provider may conduct your test at an office or in a special lung-function laboratory. They’ll place soft clips on your nose. The clips help you breathe in and out only through the mouthpiece attached to the spirometer.

You’ll then take a deep breath in and blow forcefully into the spirometer through the mouthpiece. The spirometer measures the amount of air you blow out of your lungs and the amount you inhale back into your lungs.

You’ll repeat the test at least three times to ensure your results are accurate and reproducible.

Your healthcare provider may also ask you to breathe in a medicine that helps open your airways. You’ll then perform testing on the spirometer again. Your healthcare provider will compare the results of your tests before and after you inhaled the medicine. They’ll then decide if they can use the medicine in your treatment plan.

Is a spirometry test painful?

No, a spirometry test isn’t painful.

But you may feel dizzy, lightheaded or tired from breathing in and out so deeply. Blowing into the spirometer may also cause you to cough. These symptoms should go away shortly after you complete the test. Let your healthcare provider know if you need a break during testing.

Spirometry can also increase your heart rate. Tell your healthcare provider if you’ve had a heart attack in the past or any other conditions that affect your heart.

How long does spirometry take?

It depends on the type of spirometry that your healthcare provider orders. But in general, it takes about 15 to 30 minutes to complete the test.

What should I expect after spirometry?

After the test, you may restart any medicines your healthcare provider told you to stop taking. You can also return to your usual activities, including exercise.

Your healthcare provider will tell you when to expect your test results.

In some cases, they may also test for lung volume and diffusion capacity after a spirometry test. These tests measure your lung volume capacity, as well as the ability of your lungs to transfer oxygen to your blood. These tests supplement spirometry tests by helping your provider diagnose certain lung or breathing conditions. Your provider may conduct these tests regularly to see how your breathing is progressing.

What is a normal reading on a spirometer?

A “normal” spirometer reading depends on a few factors, including your:

• Sex assigned at birth.

Your healthcare provider will use these characteristics to determine a typical reading for your demographic.

Spirometry measures two main components:

• Forced vital capacity (FVC). FVC is the highest amount of air you can forcefully and completely blow out after taking a deep breath in.
• Forced expiratory volume (FEV1). FEV1 is the amount of air you blow out in one second.

Once you’ve taken your test, your healthcare provider will compare your score against the typical reading for your demographic. A normal reading is 80% or higher than the typical demographic reading.

Your readings can also help your healthcare provider determine what kind of condition is affecting your lungs. These may include:

• Obstructive lung disease. Damage to your lungs or airways makes breathing out all the air in your lungs difficult. Common causes of obstructive lung disease include asthma, bronchiectasis, COPD and cystic fibrosis.
• Restrictive lung disease. You can’t fully expand your lungs. Common causes of restrictive lung disease may include amyotrophic lateral sclerosis (ALS), interstitial lung disease, muscular dystrophy, sarcoidosis and scoliosis.

When should I know the results of spirometry?

You won’t know your spirometry test results right after you finish. A specialist must first examine your test results, and they’ll discuss your results with the healthcare provider who ordered the test.

You should expect to get your test results within a few days.

How do spirometry test results help my healthcare provider?

Spirometry test results help your healthcare provider determine:

• If your symptoms are the result of asthma or another condition.
• If there’s a blockage or narrowing in your airways.
• If treatment is working.
• If your lungs are lower in volume than normal, which may require more testing.
• If a pulmonary disease is stable or getting worse.
• The severity of your disease.

When should I call my healthcare provider?

Your healthcare provider will contact you a few days after spirometry testing to discuss your results. Reach out to your healthcare provider if you don’t hear from them with your results after a few days.

You may have to schedule lung function tests every year if you have a chronic (long-lasting) lung disease.