Lung Function Tests Lung (or pulmonary) function tests are a variety of tests that measure how well a person breathes. They can be used to help diagnose asthma, as well as to assess the severity of a person's asthma and how effectively it's being managed. One example of a lung function test is called spirometry, which involves breathing into a device that records how much and how quickly air can be breathed out following a deep breath in. Back to Articles Related Articles Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.