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Pulmonary Function Test

A pulmonary function test (PFT) evaluates how well the lungs are working. The test measures how much air the lungs can hold, and how well the child can push air out of his or her lungs.


The machine that performs the PFT is a confined space with clear walls and a seat inside. Your child will be asked wear a nose plug and blow into a plastic mouthpiece connected to the machine. The machine measures the amount of air breathed in and the force of the air breathed out. Your child will probably be asked to repeat the test a few times to get an accurate reading.

This is a painless test and one that does not have side effects.However, pulmonary function tests require the cooperation of the child. Children can begin to perform this test around 7 years of age.

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The information and content provided on this website is made available for informational purposes only for children and their families affected by cancer. While the Children's Oncology Group strives to provide accurate and up-to-date information, the information may be out of date or incomplete in certain respects. Please do not rely on this information and seek the care of a qualified medical professional if you have questions regarding a specific medical condition, disease, diagnosis or symptom. The information and content presented herein is not intended to replace the independent clinical judgement, medical advice, screening, health counseling, or other intervention performed by your (or your child's) health care provider. Please contact "911" or your emergency services if this is a health emergency. No endorsement of any specific tests, products, or procedures is made herein.