To diagnose asthma, a doctor may give your child breathing tests, called lung function tests, along with asking about your child's symptoms.
These tests show how well your child's lungs are working.
They can show how severe asthma is or check for problems when asthma is being treated.
Your child may do a couple different kinds of breathing tests.
Peak expiratory flow—or peak flow— shows how much air your child can breathe out when exhaling as hard as they can.
Your child blows into a device called a peak flow meter.
This test can be done in a doctor's office or at home.
It may be done multiple times over a week or two.
Peak flow is often used if your child has symptoms that come and go, but the results for other breathing tests have been normal.
Spirometry shows how well your child can move air in and out of the lungs.
Your child breathes into a device called a spirometer.
This test may be repeated after your child breathes in, or inhales, medicine that opens the airways in the lungs.
If these first tests have normal results, your child may repeat the test again after taking medicine that constricts, or narrows, the airways— or after exercising, or breathing cold air, or breathing in an allergen or irritant that may be causing symptoms.
These "challenge tests," as they're called, are only done if the doctor needs more information to diagnose asthma.
They may cause symptoms, like trouble breathing.
Most of the time, breathing tests are only used for children around age 5 and older.
So if your child is younger than that, the doctor may diagnose asthma based only on symptoms.
Along with breathing tests, the doctor may do other kinds of testing, like a chest X-ray, to rule out other health problems.
If your child is getting tested for asthma, it might help to let them know what to expect.
Remind your child that the tests don't hurt, and that they'll be over quickly.
And be sure to talk to your child's doctor if you have any concerns about the tests.
