How is COPD diagnosed?

On this page we explain the types of tests you might have to diagnose COPD.

If you have symptoms of COPD, you should make an appointment with your GP.

On this page:

• What will the doctor ask me?
• What tests will I have?
  1. Spirometry
  2. Chest X-ray and blood test
  3. BMI calculation
  4. Other tests
• Specialist care and support

What will the doctor ask me?

Your health care professional will ask:

• if you cough
• if you have a lot of phlegm (mucus) 
• if your breathlessness is brought on by anything
• how your daily life is affected
• other questions about your general health and medical problems you have had in the past
• if you smoke or if you’ve ever smoked
• about your work history, and if you’ve been exposed to dust, fumes or chemicals through your work
• about childhood chest problems.

What tests will I have?

Spirometry

To get an accurate diagnosis of COPD, you should have a simple test called spirometry. This involves blowing hard and fast into a machine that measures your lung capacity. This is the total amount of air you can breathe out, and also how quickly you can empty your lungs. Healthy people can empty at least 70% of the air from their lungs in the first second of a hard blow out. 

Spirometry only covers one aspect of your lung function. People with the same spirometry result may be more, or less, breathless depending on their level of fitness, any other medical conditions and the exact way COPD has damaged their lungs.

Chest X-ray and blood test

For most people, a firm diagnosis of COPD can only be confirmed by spirometry. It will not be made with a chest X-ray on its own. However, your health care professional should arrange for you to have a chest X-ray or scan and a blood test to rule out other causes of your symptoms. 

BMI calculation

Your doctor will calculate your body mass index (BMI) to find out if you’re a healthy weight. This is important because you can manage your COPD better if you’re not underweight or overweight.

Other tests

Your health care professional may want to get a better picture of your condition and how it affects you, including:

• tests to find out how well your lungs are functioning 
• tests to see if the oxygen level in your blood is significantly reduced
• carrying out general tests, including measuring heart rate, blood pressure, and temperature
• asking how often you have symptom flare-ups or chest infections
• finding out how short of breath you feel during everyday activities.

Specialist care and support

You may also see a specialist doctor or nurse to confirm the diagnosis or to work out the right treatment for you:

• physiotherapists – to help you deal with your phlegm (mucus), control your breathing and keep active
• dieticians – to help you manage your weight
• occupational therapists – to help make your daily living easier
• counsellors or talking therapists – to help your mental wellbeing
• if you smoke, stop smoking advisors – to help you quit.

Next: What are the treatments for COPD?