Overview
Pulmonary function tests, often called PFTs, are non-surgical tests that measure how well the lungs and airways work. They can check how much air you can breathe in and out, how fast you can blow air out, and how well gases move across the lungs. Common types include spirometry, lung volume testing, and diffusion testing.
Key Symptoms
A healthcare professional may suggest these tests if you have symptoms such as shortness of breath, wheezing, chronic cough, chest tightness, or reduced exercise tolerance. They may also be used when breathing symptoms are getting worse or are not fully explained by an exam alone. Sometimes PFTs are done even when symptoms are mild, to help clarify what may be affecting breathing.
Who Is Affected
People of many ages may need pulmonary function testing, although the type of test and how well it can be performed depend on age and ability to follow instructions. These tests are often used in people with suspected or known asthma, COPD, interstitial lung disease, or occupational exposure to dusts, fumes, or chemicals. They may also be used before some surgeries or to monitor the effects of treatment.
Diagnosis and Tests
Pulmonary function testing is usually done in a clinic, hospital, or specialized lung lab. You may be asked to breathe normally, take a very deep breath, or blow out as hard and fast as you can into a device. In some cases, the test is repeated after using an inhaled medicine to see whether airflow changes. The results do not usually give a diagnosis by themselves, but they provide important information alongside your symptoms, exam, and other tests.
Living With It
If you are scheduled for pulmonary function tests, follow the instructions given by your healthcare team about eating, smoking, exercise, or using inhalers before the test. Wearing loose clothing can make breathing efforts more comfortable. Ask when and how you will receive your results, and whether repeat testing may be needed to monitor changes over time.
When to Seek Medical Care
Contact a healthcare professional if you have ongoing cough, wheezing, breathlessness, or trouble doing usual activities because of breathing symptoms. Seek medical advice if you have questions about how to prepare for the test or whether to take your regular breathing medicines beforehand. Also ask for medical review if test results are unclear to you or if symptoms change after testing.
When It May Be an Emergency
Get urgent medical help right away if you have severe shortness of breath, chest pain, blue or gray lips, fainting, confusion, or trouble speaking because of breathing difficulty. These symptoms need immediate medical assessment whether or not pulmonary function testing is planned. Do not delay urgent care while waiting for a test appointment or results.
Questions to Ask a Healthcare Professional
You may want to ask: What type of pulmonary function test am I having, and what does it measure? How should I prepare, and should I use my inhalers before the test? What do my results show, and do I need repeat testing or other lung tests? Could anything affect the accuracy of my results, such as a recent infection or difficulty performing the breathing maneuvers?