Spirometry measures the volume of air you can blow out and the speed you can do it. It is the standard test for diagnosing and monitoring conditions that narrow the airways.
Why it is requested
- Diagnosis of asthma and COPD
- Long-standing cough or breathlessness
- Monitoring known lung disease over time
- Assessing the response to an inhaler
- Lung assessment before surgery
- Occupational lung disease
Preparation
- Avoid a heavy meal in the two hours beforehand
- Do not smoke on the day of the test
- Ask whether to withhold your inhalers — this depends on the question being asked, so follow the instruction you are given
- Wear clothing that does not restrict your chest
During the test
You breathe in fully, seal your lips around a mouthpiece and blow out as hard and as long as you can. It is repeated several times, since the test depends on maximum effort. It can leave you briefly light-headed or make you cough, which settles quickly.
