You should see a GP for advice if you develop a persistent cough so they can look for a possible cause. The GP will ask you about your symptoms, such as how often you cough, whether you bring up any phlegm (sputum), and whether you smoke.

They may also listen to your lungs with a stethoscope as you breathe in and out. The lungs of people with bronchiectasis often make a distinctive crackling noise as a person breathes in and out.

You'll also probably have a chest X-ray to rule out other, more serious, causes of your symptoms, such as lung cancer. If the GP thinks you may have a lung infection, they may take a sample of your phlegm so it can be checked for bacteria.

Referral to a specialist

If the GP suspects you could have bronchiectasis, you'll be referred to a doctor who specialises in treating lung conditions (a respiratory consultant) for further testing.

Further testing

HRCT scan

Currently, the most effective test available to diagnose bronchiectasis is called a high-resolution CT (HRCT) scan. A HRCT scan involves taking several X-rays of your chest at slightly different angles. A computer is then used to put all the images together.

This produces a very detailed picture of the inside of your body, and the airways inside your lungs (the bronchi) should show up very clearly.

In a healthy pair of lungs, the bronchi should become narrower the further they spread into your lungs, in the same way a tree branch separates into narrower branches and twigs. If the scan shows that a section of airways is actually getting wider, this usually confirms bronchiectasis.

Other tests

Other tests can be used to assess the state of your lungs and to try to determine what the underlying cause of your bronchiectasis may be. These tests may include:

• blood tests – to check how well your immune system is working and check for infectious agents, such as bacteria, viruses and fungi
• phlegm (sputum) test – to check for bacteria or fungi
• a sample of your sweat can be tested to see how much salt is in it – high levels of salt can be caused by cystic fibrosis (if this test is positive, a more detailed genetic test can be carried out
• lung function test – a small, handheld device (a spirometer) that you blow into is used to measure how hard and how quickly you can expel air from your lungs; this can assess how well your lungs are working
• bronchoscopy – a flexible tube with a camera at one end is used to look into your lungs; this is usually only required if you think you have inhaled a foreign object