Pulmonary Function Testing

Lung function testing also called pulmonary function testing (PFT) is a group of tests that are performed to see how well your lungs work and function. The test measures how much air you take in (inhale), how much air you blow out (exhale), how well your lungs deliver oxygen and the strength of your breathing muscles.

The lung function test can diagnose various lung diseases including asthma, COPD and pulmonary fibrosis. The test may also be used to determine how well treatments and medicines are working to treat lung diseases. Doctors suggest the test when the patient is having symptoms of lung and breathing problems.

The pulmonary function test may be ordered to diagnose the following lung and breathing conditions:

• asthma
• allergies
• chronic obstructive pulmonary disease (COPD)
• lung fibrosis
• respiratory infections
• chronic bronchitis
• emphysema
• lung cancer/tumor

Before the PFT procedure, your doctor may ask you to stop taking your medications including asthma medications and over the counter pain medications. Avoid food and drinks that have caffeine such as coffee, tea and chocolate. Do not smoke before the test.

A lung function test usually starts with a spirometry, a test to measure the air you inhale and exhale. This test involves a machine that you breath into through a mouthpiece. The doctor may ask you to breathe normally or to breathe deeply or rapidly for several seconds. Sometimes medication is given to see how well your breathing improves after your airways are opened up.

Next, you may partake in a plethysmography test, a test that measures the volume of gas in your lungs. The doctor will then share your results with you and diagnose your condition based on the results. 

Lung function testing is normally a safe procedure. However, the following complications may occur:

• light-headedness during the Pulmonary Function testing
• fainting
• asthma attack
• collapsed lung