Pulmonary Function Testing (PFT) comprises a series of non-invasive tests that measure lung function and respiratory efficiency. These tests are crucial in diagnosing and managing respiratory conditions such as asthma, chronic obstructive pulmonary disease (COPD), and other disorders affecting breathing.

What are pulmonary function tests?

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).

What are the types of lung function tests?

• Spirometry. Spirometry measures how much air you can inhale and exhale. It also estimates how much air is in your lungs.
• Lung volumes or body plethysmography. Lung volumes or body plethysmography measure the various amounts of air that are in your lungs after different points of inhalation and exhalation.
• Gas diffusion study. A gas diffusion study measures how much oxygen and other gases transfer from your lungs to your blood.
• Cardiopulmonary exercise test (CPET). A CPET measures how well your heart, lungs and muscles work while you’re exercising.

When is pulmonary function testing performed?

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.

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.