A spirometer is a medical device used to measure the volume of air inhaled and exhaled by the lungs. It helps assess lung function and can diagnose conditions like asthma, chronic obstructive pulmonary disease (COPD), and other respiratory disorders. The test typically involves taking a deep breath and exhaling forcefully into the device. Spirometers can be found in hospitals, clinics, and even at home for monitoring lung health. The results provide valuable information about lung capacity and airflow, which can guide treatment decisions. Regular spirometry tests can help track changes in lung function over time.