Diagnosis of COPD

Your doctor may suspect COPD because of your symptoms. It can usually be diagnosed in early or mild COPD by  your Doctor using a stethoscope and asking detailed questions about your symptoms, such as how long you have had them, whether you smoke etc

Often the chest will show signs of being over-inflated (hyperinflation), this is because the airways are obstructed and it is difficult to get air both into and out of the lungs.

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

If further tests are required then the most common one to assist in diagnosing the condition is called a Spirometry test, which estimates lung volumes by measuring how much air you can blow out into a machine.

Two results are important:

  • The amount of air you can blow out in one second (called forced expiratory volume in 1 second - FEV1)
  • The total amount you can blow out in one breath (called forced vital capacity - FVC).

Your age, height and sex affect your lung volumes. So, your results are compared to the average predicted for your age, height and sex.

A value is calculated from the amount of air that you can blow out in one second divided by the total amount of air that you blow out in one breath (called FEV1/FVC ratio). A low value indicates that you have narrowed airways. The FEV1 compared with the predicted value shows how bad the COPD is.

COPD is divided into mild, moderate and severe groups, depending on the level of airflow obstruction. The airflow obstruction is the FEV1, measured with spirometry.

Mild (stage 1) COPD is an FEV1 at least 80% of predicted value.

Moderate (stage 2) COPD is an FEV1 between 50% and 79% of predicted value.

Severe (stage 3) COPD is an FEV1 between 30% and 49% of predicted value.

Very severe (stage 4) COPD is an FEV1 less than 30% of predicted value.

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

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

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