Spirometry is a breathing test to find out how well your lungs are working.
What does spirometry involve?
Spirometry is a simple test that is not painful. You will be asked to blow into a device called a spirometer which measures how much air you can breathe out of your lungs. First, you breathe in fully and then seal your lips around the mouthpiece of the spirometer. You then blow out as fast and as far as you can until your lungs are completely empty. You will also be asked to breathe in fully and then breathe out slowly as far as you can. You will need to repeat this test a few times to ensure the measurements are accurate and consistent. You will be given time to recover between tests. You may feel a bit puffed or lightheaded afterwards. If this doesn't pass quickly, let the staff know.
The test usually takes between 15 to 30 minutes.
Some people may be given an inhaled medication that relaxes and opens the airways (called a bronchodilator). Spirometry is then repeated after 15 minutes to test for any improvement in lung function.
(National Asthma Council, Australia, 2010)
How do I prepare for a spirometry test?
You should receive specific instructions from the doctor, nurse, or hospital department that does this test. Always follow these carefully. If you are on any inhalers, take these along with you to your appointment. You may be asked to avoid things that can affect your breathing before the test, such as:²
- using a bronchodilator inhaler
- drinking alcohol or drinks containing caffeine
- eating a large meal
- wearing tight clothing that makes it difficult for you to take a deep breath
- doing strenuous exercise
Are there any risks?
Spirometry is quite a safe test, but blowing out hard can increase the pressure in your chest, tummy (abdomen or puku) and eyes. You may be advised not to have spirometry if you have:²
- unstable angina or have had a recent heart attack or stroke
- had a recent pneumothorax (collapsed lung)
- had a recent operation on your eye, head or abdominal surgery
- recently coughed up blood and the cause is not known.
Also let the staff know if you have a cold, the flu, nausea, diarrhoea or vomiting.
What do the results mean?
Your doctor will discuss the results of your test with you. The results will show whether you have a problem with your lungs by comparing your measurements with someone of the same age, sex and size. The results can also help determine what type of lung problem you have.
Is spirometry different from peak flow meter tests?
Yes, spirometry is different from peak flow meter tests. A peak flow meter also measures how well your lungs are working by blowing into a device. It is not as accurate as spirometry but it is more convenient and you can use it at home. It is usually used to help diagnose and monitor asthma. Read more about peak flow meters.3