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Pulmonary Function Test: Lung Volume Test (Plethysmography)

What Is a Lung Volume Test (Plethysmography)?

The Division of Pulmonary Medicine at Cincinnati Children's performs lung function tests such as plethysmography.

Plethysmography measures how much air your lungs hold. Some disorders decrease or increase this measurement.

Description of the Test

Plethysmography is done with your child sitting in an enclosed plexiglass chamber that allows your child and therapist to see in and out. Your child will place padded nose clips on his or her nose and place their mouth around a clean filtered mouthpiece.

Your child will place his or her hands on their cheeks, breathe normally and "pant like a puppy." After panting, your child will go back to breathing normally, blow out air and then take a deep breath.

Length of Test

Plethysmography is performed along with a spirometry test. Both tests combined take 40 to 60 minutes.

Preparing Your Child for the Test

Please contact your physician or provider for instructions on holding medications.

Possible Side Effects of the Test

There are no side effects. Your child may resume normal activities and medications after testing. 

Last Updated 07/2019