Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

Pulmonary Function Tests

(PFT)
by Editorial Staff and Contributors
Definition

Pulmonary function tests (PFTs) are a group of breathing tests that help doctors see how well your lungs are working.

Reasons for Test

PFTs may be used to:

  • Diagnose lung conditions or diseases, such as:
  • Evaluate symptoms such as coughing , wheezing, and trouble breathing
  • Determine how well a treatment is working
  • Evaluate your lung function before a surgery
  • Measure how much a lung problem is affecting you
What to Expect
Prior to Test

  • Do not eat, smoke, or exercise 4-8 hours before testing.
  • Review your medicines with your doctor. There may be some you should stop taking before testing.
  • Wear loose-fitting clothing.

Description of Test

The technician will explain how each test is done and how the PFT devices (eg, spirometer , peak flow meter ) work. You might sit in an enclosed booth. You may have to wear a nose clip. In some cases, one or more of these tests will be done during or immediately following exercise (on a treadmill or stationary bike). Tell the technician right away if you have breathing problems, pain, or dizziness during testing.

A technician will ask you to breathe in and out in different patterns and speeds into the PFT devices. You will rest between tests.

The PFT will measure things like:

  • How hard you are blowing air out
  • How much air you can blow out
  • How much air your lungs can hold at different times

Additional tests that may be used in some situations include:

  • Challenge tests—You are exposed to a specific chemical during the PFT, and the test measures if your breathing changes due to that chemical. This is only done in limited situations, under close and careful supervision.
  • Oxygen saturation test—A small probe is painlessly strapped or clipped to one of your fingers or toes. It measures the amount of oxygen being carried in the blood.
After Test

Rest until you feel able to leave. You may be given a medicine if testing causes symptoms of a lung condition or disease (eg, wheezing, coughing, difficulty breathing).

How Long Will It Take?

20-45 minutes

Will It Hurt?

The test does not hurt. You may experience symptoms of your lung condition or disease (eg, wheezing, coughing, difficulty breathing) during or immediately following testing.

Results

Your doctor will compare the results of your tests with charts of normal values based on your age, sex, and height. Your doctor will discuss the results with you and decide if further testing or treatment is needed.

Call Your Doctor

After the test, call your doctor if any of the following occurs:

  • Chest pains
  • Headaches, nausea, muscle aches, dizziness, or general ill feeling
  • Shortness of breath or difficulty breathing

Last reviewed: September 2011 by Tajender S. Vasu, MD.

RESOURCES:
CANADIAN RESOURCES:
References:
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  • Pulmonary Function Tests (PFTs). Duke University Health System. DukeHealth.org website. Available at: http://www.dukehealth.org/health_library/care_guides/cancer/treatment_instructions/pulmonaryfunctiontesting . Accessed November 12, 2010.
  • Walsh JM. Interpreting pulmonary function test. Loyola University Medical Education Network website. Available at: http://www.meddean.luc.edu/lumen/MedEd/medicine/pulmonar/fellow/exam2.htm . Accessed October 30, 2006.