Asthma Tests

Even if you have all the common asthma symptoms, your doctor will usually only diagnose asthma after testing how well your lungs work. Airways with asthma are different than normal airways. They are more reactive and sensitive.


Common Asthma Tests

  • Spirometry: One of the most common tests to determine how well your airways work is called a pulmonary function test (PFT) or spirometry testing. Spirometry shows how well your lungs are working and if your airways are blocked. It can also be used to see how well asthma medicines work for you to reverse airway blockage. This test involves spirometry measurements taken before and after use of a short-acting bronchodilator. It is generally used to diagnose asthma in adults and children over age 4.
  • Peak Flow Testing: Peak flow testing is a simple home test that you can do to help monitor your breathing. This home test also evaluates your breathing volume like spirometry. Peak flow testing is used for monitoring asthma. As part of managing your asthma, you may be asked to do this breathing test at home on a daily or more frequent basis. You may also need to test yourself if you start to have symptoms.
  • Other Tests for Asthma: Sometimes a doctor will suspect asthma, but spirometry tests do not show any limitations in your airways. A test called Bronchoprovocation (bronk-oh-PRAH-voh-cay-shun) is a very safe and controlled spirometry test that can help your doctor understand how your airways are working. To perform this test, your doctor will provoke symptoms of asthma by giving you medicine, such as methacholine or histamine. Another method used to provoke, or increase the demands, in your lungs is exercise, such as walking on a treadmill. This is a test often used for people who have asthma symptoms when they exercise. You will feel as if you need to breathe harder and deeper to get a good breath, just as if you were running. When your lungs are working their hardest, your doctor can then use the spirometry test to see if your airflow is restricted in any way.

Written by Karen Serrano, MD

Emergency Medicine resident at the University of Wisconsin-Madison.


Reviewed by Lisa V. Suffian, MD

Instructor of Clinical Pediatrics in the Division of Allergy and Pulmonary Medicine at Saint Louis Children's Hospital, Washington University School of Medicine

Assistant Clinical Professor in the Department of Pediatrics at Cardinal Glennon Children's Hospital, Saint Louis University

Board certified in Allergy and Immunology

Last updated June 2008