Diagnosing Asthma

As there is no single test for asthma, diagnosis involves a mixture of factors. Speak to your GP if you suspect you or your child may have asthma.

Doctors smiling at child

If you suspect that you or your child has developed asthma, you must attend your G.P. to get an official diagnosis.

As there is no single test for asthma, your G.P. will make this diagnosis based on:

  • A family history of asthma, if there is one.
  • The pattern and frequency of symptoms.
  • A physical chest examination.
  • Peak flow readings or a lung function test (children must be over 5 years old).
  • A trial of asthma treatment

Before asthma can be confirmed or ruled out, the doctor may also you about other conditions which may be present, such as eczema or hay fever. You may also be asked to keep a diary of the symptoms you or your child have and when they occur.


Man talking to doctor

To confirm the diagnosis, the following tests may be performed

  • Spirometry: a simple breathing test that gives measurement of lung function including a reversibility test that measures lung function before and after a dose of reliever to see if the medication has improved your lung function.
  • Peak Expiratory Flow Rate (PEFR): this is another simple breathing test which may be measured over a period of time; such as when one has symptoms or is symptoms free. It can be performed by a G.P., in a hospital or even at home.
  • Exercise Testing: this test is used to check if exercise makes your symptoms worse.

Diagnosing Children

Asthma is difficult to diagnose in children under the age of two. This is because both wheezing and respiratory infections are common in young children and can have very similar symptoms to asthma.

If your child is under 2 years of age and the symptoms are persistent or severe, your doctor may prescribe a trial of asthma medication to support a diagnosis. In many cases, children may not be officially diagnosed until the age of 5.

Boy taking ventolin