Spirometry (Pulmonary Function Test)

Spirometry is the most basic and frequently performed test of pulmonary (lung) function. A device called a spirometer is used to measure how much air the lungs can hold and how well the respiratory system is able to move air into and out of the lungs. Because spirometry is based on a maximal forced exhalation, the accuracy of its results are highly dependent on the patient’s understanding, cooperation, and best efforts.

Spirometry differs from peak flow readings in that spirometry records the entire forced breathing capacity against time, and peak flow records the largest breathing flow that can be sustained for 10 milliseconds. Both are often used in asthma care.

Why would I need a spirometry test?
This test is used to determine the cause of shortness of breath, to rule out any kind of obstructive disease that blocks breathing, or restrictive disease that limits the expansion and capacity of the lungs. Spirometry is most often used to diagnose and monitor lung problems, such as chronic bronchitis, emphysema, pulmonary fibrosis, chronic obstructive pulmonary disease (COPD), or asthma.

Spirometry is also used to monitor how well medications for respiratory problems are working and to evaluate breathing capability prior to surgery.