Diagnosing Severe Asthma

Severe asthma is only diagnosed by a doctor after medical investigations and testing. 

It is important that uncontrolled asthma is thoroughly investigated. This means that your treating health professional will review that your diagnosis of asthma is correct and accurate, that your treatment is relevant to the type of asthma you have, and that you are taking your prescribed treatment and using your devices properly. It should also include reviewing and managing the other things that affect your asthma, like allergies, other long term conditions, and exposure to triggers and lifestyle and social factors.  

If despite managing all of these factors your asthma continues to be poorly controlled and you experience frequent flare-ups, it is likely and recommended that your GP refer you to a specialist.  


After referral, your doctor might arrange some tests so results are available by the time of your specialist appointment. These tests aim to determine what type of asthma you might have and help the specialist determine treatment appropriate to your individual condition. At your appointment with the specialist you may be asked a lot of questions, some of which you may have answered before. It is important that you answer all questions thoroughly so your specialist can understand your unique experiences. 

You should tell the doctor everything, including if you’re struggling to take your medication as prescribed, or if you’re experiencing side effects from your current treatment. Your doctor needs to know this information, so they can determine the best treatment for you. 

There is no single test to diagnose severe asthma. Everyone with asthma is different, so the tests may vary depending on your individual asthma symptoms, medical history and any other conditions that your doctor needs to assess or rule out. 

It may take time to diagnose severe asthma and find the right combination of medication to manage your symptoms and flare-ups. 

Learn more about diagnosis and testing for asthma, such as spirometry and peak flow. 

Most of these tests will be performed at a respiratory specialist centre or lung function testing laboratory.