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Chronic obstructive pulmonary disease (COPD) - Diagnosis

Talk to your GP if you have persistent symptoms of chronic obstructive pulmonary disease (COPD).

Your GP will:

  • ask about your symptoms
  • examine your chest and listen to your breathing with a stethoscope
  • ask whether you smoke or used to smoke
  • calculate your body mass index (BMI) using your weight and height
  • ask if you have a family history of lung problems

They may also arrange for you to have a breathing test called spirometry and some other tests.

Calculate your body mass index (BMI) -


A test called spirometry can help show how well your lungs are working.

You'll be asked to breathe into a machine called a spirometer. You'll be tested before and after you inhale a medicine called a bronchodilator. This medicine helps widen your airways.

The spirometer measures:

  • the volume of air you can breathe out in 1 second
  • the total amount of air you breathe out

You may be asked to breathe out a few times to get a consistent reading.

The readings are compared with normal results for your age. This will show if your airways are blocked.

Read more about spirometry

Chest x-ray

A chest x-ray can be used to look for problems in the lungs that can cause similar symptoms to COPD.

Problems that can show up on an x-ray include chest infections and lung cancer. But in some cases these do not always show up.

Blood tests for COPD

A blood test can pick up other conditions that can cause similar symptoms to COPD. For example, low iron levels (anaemia) and a high concentration of red blood cells in your blood (polycythaemia).

Sometimes your GP may carry out a blood test to see if you have alpha-1-antitrypsin deficiency. This is a rare genetic problem that increases your risk of COPD.

Further tests for COPD

You may need more tests to confirm the diagnosis or find out the seriousness of your COPD. You might also need tests to look at other causes for your shortness of breath.

This will help you and your GP plan your treatment.

These tests may include:

  • an electrocardiogram (ECG) – a test that measures the electrical activity of the heart
  • an echocardiogram – an ultrasound scan of the heart
  • a peak flow test – a breathing test that measures how fast you can breathe out
  • a blood oxygen test – a peg-like device is attached to your finger to measure the level of oxygen in your blood
  • a CT scan - an x-ray of a large area of the body to help identify any problems in your lungs
  • a mucus or phlegm sample – this may be tested to check for signs of a chest infection

Page last reviewed: 21 September 2021
Next review due: 21 September 2024

This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 9.