Diagnosing COPD 

Chronic obstructive pulmonary disease (COPD) is usually diagnosed after a consultation with your GP, as well as breathing tests.

If you are concerned about the health of your lungs and have symptoms that could be COPD, see your GP as soon as you can.

Being diagnosed early means you will receive appropriate treatment, advice and help to stop or slow the progression of COPD.

At a consultation, your doctor will ask about your symptoms, how long you have had them, and whether you smoke, or used to smoke. They will examine you and listen to your chest using a stethoscope. You may also be weighed and measured to calculate your body mass index (BMI).

Read more about BMI or use a BMI calculator.

Your doctor will also check how well your lungs are working with a lung function test called spirometery.


To assess how well your lungs work, a breathing test called spirometry is carried out. You will be asked to breathe into a machine called a spirometer.

The spirometer takes two measurements: the volume of air you can breathe out in one second (called the forced expiratory volume in one second or FEV1) and the total amount of air you breathe out (called the forced vital capacity or FVC).

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

The readings are compared with normal measurements for your age, which can show if your airways are obstructed.

Other tests

You may have other tests as well as spirometry. Often, these other tests will help the doctor rule out other conditions that cause similar symptoms.

Chest X-ray

A chest X-ray will show whether you have another lung condition which may be causing symptoms, such as a chest infection or lung cancer.

Blood test

blood test will show whether your symptoms could be due to anaemia, as this can also cause breathlessness.

Further tests

Some people may need more tests. The tests may confirm the diagnosis or indicate the severity of your COPD. This will help you and your doctor plan your treatment.

Electrocardiogram (ECG) and echocardiogram

An electrocardiogram (ECG) or echocardiogram may be used to check the condition of your heart.

An ECG involves attaching electrodes (sticky metal patches) to your arms, legs and chest to pick up the electrical signals from your heart.

An echocardiogram uses sound waves to build a detailed picture of your heart. This is similar to an ultrasound scan.

Peak flow test

To confirm you have COPD and not asthma, you may be asked to take regular measurements of your breathing using a peak flow meter, at different times over several days. The peak flow meter measures how fast you can breathe out.

Blood oxygen level

The level of oxygen in your blood is measured using a pulse oximeter, which looks like a peg and is attached to the finger. If you have low levels of oxygen, you may need an assessment to see whether extra oxygen would help you.

Blood test for alpha-1-antitrypsin deficiency

If the condition runs in your family or you developed the symptoms of COPD under the age of 35 and have never smoked, you will probably have a blood test to see if you are alpha-1-antitrypsin deficient.

Computerised tomography (CT) scan

Some people may need a CT scan. This provides more information than an X-ray and can be useful in diagnosing other lung diseases or assessing changes to your lungs due to COPD.

Other breathing tests

If your symptoms seem worse than would be expected from your spirometry results, your doctor may decide you need more detailed lung function tests. You may be referred to a hospital specialist for these tests.

Phlegm sample

The doctor may take a sample of phlegm (sputum) to check whether it has been infected.

Page last reviewed: 01/10/2014

Next review due: 01/10/2016