How is asthma diagnosed?

You should prepare to answer your doctor a number of questions regarding: 1

  • Your family history 
  • Medications you’re currently taking
  • Your daily routine.

You must share:  1

  • Symptoms
  • If you have been in contact with triggers such as animal dandruff, pollen, tobacco smoke, etc. 
  • If you’ve had a respiratory tract infection lately.

Your doctor will likely perform a physical test (for example, listening to your chest and check your nose’s interior), then look for other possibilities that may indicate what is causing your symptoms and do one of these tests. 2

Learn about the 2 most common tests for diagnosis


This test involves placing the mouthpiece of a spirometer in your mouth (after deep inhalation) and exhaling as hard and quickly as possible. This will measure the amount of air during that inhalation and exhalation, in addition to the expiratory force. This way your HCP can verify how well your lungs are working.3

Peak Expiratory Flow measurement

This test uses a Peak Flow that measures how much air a patient can breathe out (exhaling as strong as they can). Their maximum expiratory flow decreases when the ducts (bronchial tubes) that carry air to the lungs narrow. Note that the peak expiratory flow is at its lowest point early in the morning and at its highest point in the afternoon, so it is recommended that the measurement is performed in the morning before using your medication. 4  Remember to always follow your doctor´s instructions. 


  1. Asthma Overview. Ashtma and Allergy Foundation of America. Available at: Last access: October-2020
  2. Diagnosing asthma. National Asthma Council Australia. Available at: Last access: October-2020
  3. Asthma Diagnosis: Lung Function Tests. Asthma and Allergy Foundation of America. Available at: Last access: October-2020
  4. Asma: Flujo espiratorio máximo y mejor medición personal. NorthShore University HealthSystem . Available at: Last access: October-2020

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