Diagnosis of COPD
COPD is a common condition, with around 1.7 million people in the UK currently living with it; however, a lot of people do not realise they have COPD, with around 600,000 people living undiagnosed across the UK.1 You should always see your GP if you are worried about any potential COPD symptoms, like those described on this page, as they can help you get the right help and support.2
When should you see your Healthcare Team?
See your Healthcare Team if you have symptoms that don’t go away, such as:1
A cough that lasts a long time
Feeling short of breath doing everyday things
Wheezing
These could be signs of COPD or another lung condition. For more information on the symptoms of COPD, read through the ‘About COPD’ section here.
What tests might you get in your COPD journey?
Your GP is usually the first person you’ll see when starting your journey to a diagnosis. They will talk to you about your symptoms and medical history to understand any risk factors for COPD. This helps them decide which tests might be right for you.3,4
One of the main tests your GP may suggest is called spirometry, which checks how well your lungs are working. They may also recommend a few other tests, which are explained below.3,4
Keep in mind that you may not need every test listed below — it depends on your symptoms and where you are in the diagnostic process. The types of tests you have, and how quickly you get them, may also vary depending on your local healthcare services.
Breathing tests
(Pulmonary Function Tests)
Breathing tests help measure how well your lungs are working. They can show how much air you can breathe in and out, and how easily air flows through your lungs.
Spirometry
This test checks how well your lungs are working. You’ll breathe into a machine called a spirometer, usually after taking a medicine that opens your airways (a bronchodilator). The machine measures:4
- How much air you can blow out in one second
- The total amount of air you can blow out
You may be asked to repeat the test a few times to get the most accurate result. The results are compared with normal values for your age.4
Pulse oximetry
A small device is placed on your finger to measure how much oxygen is in your blood. Sometimes this is done while you walk for six minutes, to see how your lungs work during activity.5
Exercise stress test
You may be asked to walk on a treadmill or pedal a stationary bike while your heart and lungs are monitored. This checks how your body handles exercise.6
Blood gas test
This shows how well oxygen and carbon dioxide move between your lungs and your blood.5
Lung volume test
This measures how much air your lungs can hold when you breathe in and out.7
Imaging tests for COPD
Chest X-ray
A chest X-ray can show changes in your lungs that may be caused by COPD. It can also help rule out other problems like chest infections and lung cancer, though these do not always show.4
CT scan
CT scans are used to understand what’s going on inside your lungs. They can see if your lungs are healthy and can help to diagnose lung conditions. A CT scan might also be used to decide what type of treatment you need and to monitor your condition.8
Blood tests
General blood tests
These may help rule out other causes of your symptoms, such as:4
- Anaemia – low iron levels
- Erythrocytosis — a high concentration of red blood cells in the blood
Alpha-1 antitrypsin (AATD) deficiency test
This is a special blood test to check for a rare genetic condition that can cause COPD, especially in younger people.9
Arterial blood gas test
This checks how well your lungs are getting oxygen into your blood and removing carbon dioxide. It can help your doctor understand how severe your COPD is.9
Why these tests matter
These tests give your healthcare team a better picture of your condition and how much it is affecting your life. It will also ensure that the treatment plan you are given is the most effective for you, and therefore may reduce the risk of exacerbations.3
Abbreviations:
References:
- Asthma + Lung UK. What is COPD? Available at: https://www.asthmaandlung.org.uk/conditions/copd-chronic-obstructive-pulmonary-disease/what-chronic-obstructive-pulmonary-disease. Accessed November 2025.
- Asthma + Lung UK. How is COPD diagnosed? Available at: https://www.asthmaandlung.org.uk/conditions/copd-chronic-obstructive-pulmonary-disease/how-copd-diagnosed. Accessed November 2025.
- Asthma + Lung UK. Diagnosing COPD. Available at: https://www.asthmaandlung.org.uk/healthcare-professionals/copd/diagnosing-copd. Accessed November 2025.
- NHS. Diagnosis (COPD). Available at: https://www.nhs.uk/conditions/chronic-obstructive-pulmonary-disease-copd/diagnosis/. Accessed November 2025.
- Asthma + Lung UK. Oxygen level testing. Available at: https://www.asthmaandlung.org.uk/symptoms-tests-treatments/tests/oxygen-level-tests. Accessed November 2025.
- Liverpool Heart and Chest Hospital. Respiratory diagnostics. Available at: https://www.lhch.nhs.uk/respiratory-diagnostics. Accessed November 2025.
- Asthma + Lung UK. Lung volume test. Available at: https://www.asthmaandlung.org.uk/symptoms-tests-treatments/tests/lung-volume. Accessed November 2025.
- Asthma + Lung UK. Imaging scans. Available at: https://www.asthmaandlung.org.uk/symptoms-tests-treatments/tests/imaging-scans. Accessed November 2025.
- Asthma + Lung UK. Blood tests. Available at: https://www.asthmaandlung.org.uk/symptoms-tests-treatments/tests/blood-tests. Accessed November 2025.