Lung function testing in children is an important part of assessment, diagnosis and monitoring of children with lung disease. Spirometry measures how much air is moved in and out of the lungs and how fast the air moves.

Your child will be asked to wear a nose clip to keep him or her from breathing through their nose during the test. They will then be asked to take in a deep breath and blow the air out into a mouthpiece that is connected to a computer. The computer measures how much and how fast the air is blown out. He/She will repeat the test at least two times to get their best, most consistent result. This test can take up to 30 minutes to complete.

Your child may become tired or frustrated during the test and this is common. Sometimes it takes several visits to the of clinic to practice the test before your child can complete the test. Sometimes this test is repeated after your child inhales medication. This test is called a post-bronchodilator or bronchodilator response test.