Lung Function Tests

Pulmonary Function Tests

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Using medicine that expands the lungs' airways within 4 hours of the test.
• Using sedatives before the test.
• Eating food or drinks that contain caffeine before the test.
• Not being able to breathe normally because of pain.
• Pregnancy, obesity, or an enlarged stomach (after a large meal, for example).
• Not being able to follow instructions or make an effort during the tests.

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Author:	Maria Essig	Last Updated: June 7, 2009
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine Robert L. Cowie, MB, FCP(SA), MD, MSc, MFOM - Pulmonology
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