Spirometry is standard test doctors use to measure your lungs’ functioning. The test works by measuring airflow in and out of your lungs. To take a spirometry test, you sit and breathe into a small machine called a spirometer. This medical device records the amount of air you breathe in and out and the speed of your breath.
Doctors use spirometry tests to diagnose these conditions:

• COPD
• Asthma
• Restrictive lung disease, such as interstitial pulmonary fibrosis
• Other disorders affecting lung function

Spirometry can also allow your doctor to monitor chronic lung conditions to check whether your current treatment improves your breathing.