This involves doing a spirometry test, then breathing in an aerosol medicine called a ‘bronchodilator’.

Bronchodilators are designed to expand the bronchial tubes that carry air in and out of your lungs.

After you breathe in the medicine, you wait for about 20 minutes. Then you do the spirometry test again to see if your results have changed.

If you have asthma, your spirometry test improves after taking the bronchodilator.

These tests help to:

  • Decide whether you may have asthma.
  • Check how your lungs react to different medicines.
  • Decide which treatment suits you best.