If you are diagnosed with chronic obstructive pulmonary disorder (COPD), your doctor will also determine your COPD stage. A COPD stage is sometimes called a COPD grade or a GOLD stage. This is named after The Global Initiative for Chronic Obstructive Lung Disease (GOLD).1,2
Your COPD stage is a rough guideline that can help you understand your condition. It also helps your healthcare team plan treatment and track changes in your COPD.1,2
How do you find out your COPD stage?
If you are showing symptoms of COPD, you should contact a doctor. If your doctor thinks you may have COPD, they will recommend breathing tests. These tests measure how healthy your lungs are and how well you can breathe.1
The tests have 2 important purposes. They can help verify if you do have COPD. If you have COPD, these tests can help determine which stage you have.1,2
What tests are used to determine your COPD stage?
A COPD stage is determined with results from 2 breathing tests called spirometry tests. These tests are used to measure how well your lungs are working.3
These tests are called forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1). They both measure your lung function in different ways:4
- FVC – Measures the total amount of air you exhale in 1 breath
- FEV1 – Measures the amount of air you can exhale in the first second of breathing out
What happens during the spirometry tests?
The same machine is used for the FVC and FEV1 tests, and the tests use the same basic technique. This machine is called a spirometer. The spirometer has an attached mouthpiece to blow into during the tests and a sensor to measure the air you blow. If you are being tested, you will be asked to inhale the deepest possible breath into your lungs and then exhale your breath by blowing into the mouthpiece as hard as possible.1 To make sure the results are correct, this part of the test is usually repeated several times.
What do the test results mean?
Your doctor will use your spirometry test results and information about your symptoms to determine your COPD stage. One result from the test is the ratio of FEV1/FVC. This ratio combines both test results and is reported as a percentage or a decimal. The lower this value is, the less efficiently the lungs are working.1,4
Most healthy adults have a FEV1/FVC ratio between 70 and 80 percent. If your FEV1/FVC ratio is below 70 percent, it might be a sign that you have COPD.4
Another value used to classify your COPD is the predicted FEV1. The predicted FEV1 is a percentage that compares your airflow to the average airflow of other people of the same age, sex, and body type.4
Together, the FEV1/FVC ratio and predicted FEV1 can help classify your COPD. If you have a FEV1/FVC less than 70 percent, your COPD stage is based on your predicted FEV1:4
- COPD Stage I (Mild) – Predicted FEV1 greater than 80 percent
- COPD Stage II (Moderate) – Predicted FEV1 between 50 and 80 percent
- COPD Stage III (Severe) – Predicted FEV1 between 30 and 50 percent
- COPD Stage IV (Very Severe) – predicted FEV1 less than 30 percent
What other factors impact your COPD stage?
In the past, COPD stage was decided only based on spirometry test results. These test results do give important information on how well your lungs are working. But they do not determine everything about someone’s COPD. Two people could have similar spirometry test results but have different symptoms and challenges.1
Because of this, it is recommended that your doctor consider other factors when determining your stage. They should ask how often you have flare-ups, or exacerbations. They may also ask you to fill in a questionnaire like the COPD Assessment Test (CAT) or modified Medical Research Council test (mMRC).1,2
Your doctor may also use these results to assign a letter to your COPD called a group. The letter describes how serious your symptoms and risk are:1,2
- Group A – Lower risk, fewer symptoms
- Group B – Lower risk, more symptoms
- Group C – Higher risk, fewer symptoms
- Group D – Higher risk, more symptoms
Your group letter is combined with your stage number for an overall understanding of your COPD.2
It can be confusing to keep the different measures of COPD straight. If you are confused about your COPD stage, reach out to your doctor. They will be able to answer the questions on your specific COPD case.