Pulmonary Function Laboratory
Tests Offered

Tests Performed by the Pulmonary Function Laboratory

The Pulmonary Function Laboratory at Cincinnati Children’s conducts a number of tests to measure respiratory health. We coordinate with your child’s provider to perform the tests and evaluate the results. Each test involves a different procedure and measures different aspects of your child’s lung function. Your child’s test will be interpreted by a pediatric pulmonary physician and the final report will be sent to your doctor.

What are Pulmonary Function Tests (PFTs)

Pulmonary Function Tests measure how well the lungs work in different ways.

PFTs can be used to:

  • Identify if your child has a decrease in the ability for lungs to move air in and out or across tissues within the lungs themselves.
  • Measure the effects of known chronic lung diseases – such as asthma and cystic fibrosis – on your child’s lung function.
  • Decide if medication is helping or needs to be started or adjusted
  • Determine your child’s ability to tolerate medical procedures
  • Assess how exercise changes your child’s lung function

Tests

Watch a video about spirometry

This test measures how much and how fast air flows into and out of the lungs. Your child will be asked to breathe out as hard and for as long as possible into a measuring device. The test takes only a few minutes, although a complete session, with explanations and practice testing, may take up to 40 minutes. Spirometry testing is sometimes done in conjunction with other tests, such as the lung volume test (plethysmography).

Learn more about spirometry.

Watch a video about plethysmography

This test measures how much air your child’s lungs hold. Your child will sit in an enclosed Plexiglass chamber and will breathe through a mouthpiece according to the therapist’s instructions. The test is done in conjunction with a spirometry test and takes about 40 to 60 minutes to complete.

Learn more about plethysmography.

Watch a video about the diffusion test

This test measures the transfer of gases in your child’s lungs. It can help indicate the lungs’ ability to transfer oxygen into the bloodstream. The test involves your child breathing through a mouthpiece connected to a computerized monitoring machine. It is often performed with other tests and could take up to an hour to complete. Your child’s pediatrician may limit eating, exercise and/or smoking prior to the test.

Learn more about diffusion testing.

Watch a video about the methacholine challenges test.

This test is used by your child’s pediatrician to determine if your child has asthma. The therapist will have your child inhale very small doses of methacholine, a drug that may cause the airway to react or become narrow. Using spirometry tests, the therapist will measure your child’s breathing after gradually increasing doses of methacholine. The therapist will closely monitor your child and can give your child a symptom relieving treatment if necessary. This test takes up to two hours.

Learn more about the methacholine challenges test.

Watch a video about the exercise induced asthma test

In this test, your child will first breathe into a spirometer to measure airflow rate. Your child will exercise on a treadmill to reach a target heart rate. The therapist will measure heart rate and blood oxygen levels during the exercise and will ask your child to rate their level of exertion. After the run, your child will complete spirometry tests every five minutes for 30 minutes, to measure lung function after exercise. Your child should not eat three hours before the test, and your child’s physician may have your child stop taking certain medications prior to the test. This test often lasts about two hours.

Learn more about the exercise induced asthma test.

Watch a video about respiratory muscle strength test

This testing involves three separate tests that measure the strength of the muscles your child uses to breathe. The Maximal Inspiratory Pressure (MIP) test measures the strength of muscles used to take deep breaths. The Maximal Expiratory Pressure (MEP) test measures the muscles used to cough. And the Maximum Voluntary Ventilation (MVV) measures both sets of muscles together and gives the therapist an idea of how well your child can breathe in and out. The tests usually take less than 20 minutes.

Learn more respiratory muscle strength test.