Pulmonary Function Tests
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:
- Measure how much a lung problem is affecting you
- Evaluate symptoms such as ]]>coughing]]> , wheezing, and trouble breathing
- Determine how well a treatment is working
- Evaluate your lung function before a surgery
What to Expect
Prior to Test
- Review your medicines with your doctor. There may be some you should stop taking before testing.
- Do not eat, smoke, or exercise 4-8 hours before testing.
- Wear loose-fitting clothing.
Peak Flow Meter
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 much air you can blow out
- How much air your lungs can hold at different times
- How hard you are blowing air out
Additional tests that may be used in some situations include:
- 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.
- 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.
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?
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.
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.
American Lung Association
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Crapo RO, Casaburi R, Coates AL, et al. Guidelines for methacholine and exercise challenge testing (1999). Am J Respir Crit Care Med . 2000;161:309.
Pulmonary function tests. National Library of Medicine, Medline Plus website. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/003853.htm . Accessed October 16, 2007.
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.
Last reviewed October 2009 by ]]>Rosalyn Carson-DeWitt, MD]]>
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.
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