Pulmonary Function Tests: Types of Tests

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What are the different types of PFTs?

There are many types of PFTs. The PFTs your child has depends on their symptoms and medical history.

Different types of pulmonary function tests

There are many types of PFTs. The PFTs your child has depends on their symptoms and medical history. Here are common types of PFTs your child might have:

Forced vital capacity flow-volume loop
This test measures the amount of air and how quickly it can move through the lungs in one strong, deep breath. Your child will take a deep breath and exhale as hard as they can into the spirometer (a tube used to measure the amount of air breathed out of the lungs). They will do this a few times with help from the care team.

Lung volume tests
Some common lung volume tests include plethysmography, helium dilution test and nitrogen washout test. These tests check how well your child’s lungs are working. They also check for different lung or airway diseases or defects. For these tests, your child will sit inside of a body/box chamber. The chamber looks like a telephone booth with clear walls, a seat inside and a mouthpiece on one side. The care team will sit at a computer next to the chamber. For this test, your child will take several small breaths into the mouthpiece with the help of the care team.

Single breath diffusion capacity test
This test checks how much air passes through the lungs, into the blood and out to the rest of the body. For this test, your child will take two breaths into a spirometer that is connected to a computer. They will then hold their breath for 10 second. They will do this a few times with the help of the care team.

Fractional Expired Nitric Oxide (FENO) test
A FENO test is used with a forced vital capacity flow-volume loop test to check the lungs of children with asthma. It measures how much nitric oxide (a gas produced during an exhale) flows out of the lungs.

Capnography test
A capnography test (also called an EtCO2 test) checks how much carbon dioxide (a gas produced during an exhale) flows out of the lungs. For this test, your child will breathe normally into a tube connected to a computer.

Oxygen saturation test
An oxygen saturation test measures how much oxygen is flowing through the blood. For this test, the care team will place a small, plastic monitor on their finger for 2-3 minutes. This does not hurt.

Maximum airway pressure test
This test is for children who have neuromuscular diseases (diseases that affect the nerves in the muscles and how they work). This test checks how much pressure is put on the lungs during an inhale.

Cardiopulmonary exercise test
This test (also called a stress test) checks how well your child’s heart and lungs work at rest and during intense exercise. The test usually lasts 45 minutes to an hour. The exercise part lasts for about 10 minutes. For this test, your child will use a treadmill or stationary bike to raise their heart rate.

Rev. 10/2018. Reviewed by the MGfC Family Advisory Council. Mass General for Children and Massachusetts General Hospital do not endorse any of the brands listed on this handout. This handout is intended to provide health information so that you can be better informed. It is not a substitute for medical advice and should not be used to treatment of any medical conditions.