What is pulmonary function testing?
Pulmonary refers to your lungs. Pulmonary function tests check how well your lungs are working.
During the test, you breathe in and out of a tube connected to the pulmonary function device
The device measures how much air goes in and out of your lungs and how fast the air moves
Pulmonary function tests look for lung diseases, such as asthma Asthma Asthma is a condition in which the breathing passages (airways) in your lungs get narrow. When the airways are narrow, it's hard to breathe. Breathing often makes a squeaky musical sound called... read more
or emphysema Chronic Obstructive Pulmonary Disease (COPD) COPD is a disease in your lungs that makes it hard to breathe. It's hard to push air out of your lungs. Difficulty pushing air out is called chronic airflow obstruction. Smoking cigarettes is... read more 
How do doctors do pulmonary function tests?
Doctors can use several different devices. The most common ones are:
Spirometers
Peak flow meters
Spirometers
A spirometer is a device you breathe into to measure how much air your lungs can hold and how fast you can blow air out of your lungs. Doctors use a spirometer:
To see if something is blocking your breathing passages
To see how much air your lungs hold
To check how strong your breathing muscles are
Spirometer
 A spirometer can be used to measure how much air the lungs can hold and how quickly air can be exhaled. |
Peak flow meters
A peak flow meter measures only how fast you can blow air out of your lungs. It's a small device you hold in your hand. If you have asthma, your doctor may give you one to use at home to keep track of how you're doing.
Why do doctors do pulmonary function tests?
Doctors do pulmonary function tests to see how well your lungs are working. They may do them if you have or may have a disease that affects your lungs or breathing muscles, such as:
Doctors can use pulmonary function tests to check for:
What kind of lung disease you may have
How severe your lung disease is
How well your breathing medicine is working
