Pulmonary Function Test

Getting to the bottom of your breathing issues

If you are having trouble breathing, your doctor may ask you to take a breathing test called a pulmonary function test. This test measures how well your lungs are functioning and the results will help you and your doctor find out what’s causing the problem.

Pulmonary function tests (sometimes called a PFT) help diagnose lung conditions such as asthma or bronchitis. If you have already been diagnosed with a particular lung condition, a pulmonary function test can also determine how well the medication you’re taking for the condition is working.

A pulmonary function testing is also sometimes done if you have shortness of breath, a history of smoking or if you are planning to have a lung transplant.

How the test is done

The test itself is fairly simple. You will go to the pulmonary function lab where a pulmonary therapist will check your weight and height. That allows the pulmonary specialists to determine what your normal values should be based on your size, gender, age and nationality. In other words, the test will determine what is optimal for you.

In the testing area you will be taken to a clear booth. The therapist will instruct you how to breathe — taking big breaths in and out; holding your breath for a few seconds; or taking short quick breaths or long breaths — depending on what your physician ordered. The tests may be repeated to assure complete and accurate representation of your breathing function.

Once the test is done, the results will be analyzed and interpreted by a pulmonary specialists and recorded in your electronic medical records so you and your primary care physician can review and discuss them.

Results

You and your doctor will discuss your results. The results of the test and your diagnosis may determine the next steps of your care

What to Expect from a Pulmonary Function Test

Pulmonary function tests (sometimes called a PFT) help diagnose lung conditions such as asthma or bronchitis. If you have already been diagnosed with a particular lung condition, a pulmonary function test can also determine how well the medication you’re taking for the condition is working.

A pulmonary function testing is also sometimes done if you have shortness of breath, a history of smoking or if you are planning to have a lung transplant.

How the test is done

The test itself is fairly simple. You will go to the pulmonary function lab where a pulmonary therapist will check your weight and height. That allows the pulmonary specialists to determine what your normal values should be based on your size, gender, age and nationality. In other words, the test will determine what is optimal for you.

In the testing area you will be taken to a clear booth. The therapist will instruct you how to breathe — taking big breaths in and out; holding your breath for a few seconds; or taking short quick breaths or long breaths — depending on what your physician ordered. The tests may be repeated to assure complete and accurate representation of your breathing function.

Once the test is done, the results will be analyzed and interpreted by a pulmonary specialists and recorded in your electronic medical records so you and your primary care physician can review and discuss them.

Results

You and your doctor will discuss your results. The results of the test and your diagnosis may determine the next steps of your care

What to Expect: Pulmonary Function Test

Because you’ll be doing a lot of breathing, do not eat a heavy meal before the test. If you are a smoker, refrain from smoking for four to six hours before the test. If you use bronchodilators, you will be given specific instructions on their use prior to the test from your physician’s office.

Preparing for a Pulmonary Function Test

Because you’ll be doing a lot of breathing, do not eat a heavy meal before the test. If you are a smoker, refrain from smoking for four to six hours before the test. If you use bronchodilators, you will be given specific instructions on their use prior to the test from your physician’s office.

You may feel a little light headed or woozy after the test due to all the breathing. Be sure to report anything you are feeling to the respiratory therapist.

After Your Pulmonary Function Test

You may feel a little light headed or woozy after the test due to all the breathing. Be sure to report anything you are feeling to the respiratory therapist.

Be sure to write down questions you may have. Here are a few questions to get you started:

  • Why do I need this test?
  • What questions will it answer?
  • How long will it take?
  • When will I get my results?
  • Should I stop any medication before the test?

​Questions To Ask Your Physician

Be sure to write down questions you may have. Here are a few questions to get you started:

  • Why do I need this test?
  • What questions will it answer?
  • How long will it take?
  • When will I get my results?
  • Should I stop any medication before the test?

MedLine Plus

Provides information on how a pulmonary function test is performed.

Resources

MedLine Plus

Provides information on how a pulmonary function test is performed.

Patient Stories for Pulmonary Function Test