Spirometry is a commonly used lung test to evaluate the functioning of the lungs. Spirometry is done to measure the airflow in and out of the lungs, and it also measures the amount of air exhaled and how quickly the person can exhale the same amount of air. Spirometry is a test performed to measure the lung capacity along with its functioning. Spirometry is helpful in diagnosing some medical conditions like chronic pulmonary obstructive disorder (COPD), restrictive lung disease (e.g. interstitial pulmonary fibrosis), asthma and other problems that affect the breathing cycle. This test also assists the doctor to evaluate the response of treatment of chronic lung condition. Spirometry is an effective test that helps in identifying any blockages in the airways, which can be treated by giving medication to the patient to open the airways. These medications are also known as bronchodilator. After few minutes of administering the bronchodilator, the spirometry test is performed again to check if the bronchodilator has helped the patient or not in improving the symptoms or the disease condition.