Pulmonary Function Test (PFT)
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 sometimes 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.