Spirometry for Asthma

When you need the test—and why

Spirometry is a simple breathing test. It measures how much air flows in and out of your lungs. If you have symptoms that could be a sign of asthma—like shortness of breath—you should have a spirometry test. Here’s why:

Asthma and other diseases can have the same symptoms.

When you have asthma, the lining of the airways in the lungs swells and the muscles around the airways get tight. Then the airways get narrow.

When you breathe, you have trouble moving air out of your lungs. As a result, you may cough, wheeze, feel short of breath, or have tightness in your chest. Exercise or cold air may make the symptoms worse.

However, those same symptoms can also be a sign of other lung problems, such as a common cold, bronchitis, or pneumonia. They can even be symptoms of heart disease and other diseases.

It is important to know the cause of your symptoms to make sure you get the right treatment. The treatment for asthma is very different from the treatment for pneumonia or heart disease.

Spirometry helps diagnose and manage asthma.

A spirometry test can confirm whether you have asthma or another disease. And it helps your health-care provider decide on your treatment.

A spirometry test can also show how well your treatment is working. If follow-up spirometry tests show that your asthma is well controlled, your treatment is working. If it shows that your asthma is not under control, your doctor may need to change your medicine or give you more medicine.

Skipping the test has risks.

Many people who need a spirometry test never have one. Some health-care providers only rely on symptoms to decide whether a patient has asthma or another disease.

If your doctor assumes you have asthma without giving you a spirometry test, you could be taking asthma drugs when you don’t need them. And the real cause of your symptoms would not be treated.

On the other hand, you and your doctor might assume the cause of your symptoms is a mild problem, when in fact it is asthma. If your asthma is not treated, you could have severe asthma attacks. About nine people die from asthma attacks every day in the U.S. Untreated or poorly managed asthma can also cause scarring in the lungs, which can lead to COPD. Once the lungs are scarred, asthma medicines won’t work as well.

The test can save money.

A spirometry test generally costs less than $100. Not having the test can cost a lot more money. If the test shows that you do not have asthma, this can save you $200 to $300 a month for asthma medicines. If you do not have the test and you have asthma, an emergency room visit for an asthma attack can cost $3,500 or more.

When should you have a spirometry test?

Children age five or older, and adults of any age, who have asthma-like symptoms should have a spirometry test. Your health-care provider should also do a physical exam and a full medical history. If the test shows that you have asthma, your doctor should prescribe asthma medicine. Then you should be retested four to six weeks later. If your test results improve, your treatment is working. You may even be able to take less medicine. If your symptoms get worse, you should have another spirometry test. If your symptoms are controlled, you should have a test at least once every year or two.

This report is for you to use when talking with your health-care provider. It is not a substitute for medical advice and treatment. Use of this report is at your own risk.

© 2013 Consumer Reports. Developed in cooperation with the American Academy of Allergy, Asthma & Immunology. To learn more about the sources used in this report and terms and conditions of use, visit: ConsumerHealthChoices.org/about-us/.