Pulmonary function tests (PFTs) include different kinds of breathing tests that measure how well your lungs exchange air. Your lungs help you take air in (inhale) and breathe air out (exhale).There are many different types of PFTs. Some also measure how well your lungs absorb oxygen into your blood and how exercise affects your lungs.PFTs are safe and don’t require a healthcare provider to put any tools or instruments inside your body (noninvasive).Another name for pulmonary function tests is lung function tests.
Your healthcare provider may order pulmonary function tests if you have lung or airway symptoms like cough or shortness of breath, are undergoing surgery or use tobacco products (smoke). These symptoms may include:
Chest tightness, pain or pressure, Coughing, especially if you produce mucus or phlegm, Difficulty breathing or taking a deep breath, Shortness of breath (dyspnea),Wheezing.
Even if you don’t have symptoms, your healthcare provider may order a pulmonary function test as part of a routine physical examination.

PFTs also help your healthcare provider:
# Detect narrowing in your lungs’ airways.
# Identify early changes in your lungs’ ability to transfer oxygen to your blood.
# Measure the effects of continued smoking on chronic pulmonary diseases.
# Decide if medications may help improve your breathing.
# Understand if exposure to substances in your environment has affected your lungs.
# Determine your ability to tolerate surgery or other medical procedures.
PFTs help your healthcare provider diagnose:

Asthma.
Chronic obstructive pulmonary disease (COPD).
Pulmonary fibrosis.
Weakness of your breathing muscles.
Narrowing of your trachea