Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor provides Pulmonary Function Tests?
A pulmonologist, a doctor who treats lung disease, or your primary care doctor can order pulmonary function tests. Your health care provider may order one or more lung function tests, depending on the reason you need to be tested. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What it is
Pulmonary function tests are a group of tests that measure breathing and how well the lungs are functioning. They are also called PFTs or lung function tests. Most of them involve breathing through a mouthpiece.
Common lung function tests include the following.
- A spirometry test measures how much air you breathe out and how fast you can blow air out of your lungs.
- Body plethysmography, a lung volume test, is the most accurate way to measure the amount of air your lungs can hold.
- A lung diffusion capacity test measures how well your lungs deliver oxygen to your blood from the air you breathe.
- Exercise tests measure how well your lungs work when you are active.
Why a doctor might recommend it
Lung function tests are often used for the following reasons.
- To help diagnose and monitor lung diseases.
- To check lung function before surgery.
- To check for lung damage from exposure to chemicals or other substances at home or work.
You may need testing if you have signs or symptoms of a breathing problem, such as wheezing or coughing.
How to prepare
Your provider will let you know how to prepare for your lung function test.
- Do not eat a large meal within at least two hours of the test.
- You may need to avoid heavy exercise, smoking, alcohol, and caffeine before the test, and your provider will tell you for how long.
If you use inhaler medicines, called bronchodilators, you may need to stop for a period of time before testing. Your provider will tell you when to stop. Never stop taking any medicine without talking with your provider first.
What happens during it
For a spirometry test, you sit on a chair with a soft clip on your nose. The clip makes sure you breathe only through your mouth. You place your lips tightly around a mouthpiece that is connected to a device called a spirometer. You take a deep breath in and then blow it out into the mouthpiece as hard as you can.
For a body plethysmography test, you sit in a small, airtight room with clear walls. Air pressure changes inside the room show how much air your lungs can hold and how much air stays in your lungs after you breathe out.
For a gas diffusion test, you breathe in a very small, safe amount of carbon monoxide gas. Then you hold your breath for about 10 seconds.
Recovery
Your provider will compare your results to results from healthy people who are the same height, age, and sex as you. If you have questions about your results, talk with your provider. Call 911 or go to the emergency room if you have trouble breathing, chest pain or discomfort lasting two minutes or more, fainting, coughing up or vomiting blood, or bleeding that will not stop.
Risks and side effects
There is very little risk to having a lung function test. Some people may feel lightheaded, dizzy, or tired from breathing hard. There is a small risk of a collapsed lung, called a pneumothorax, in people with a certain type of lung disease.
Who performs it
A technologist asks you to breathe in and out of a mouthpiece during the lung volume test.
Common questions
What do my results mean?
Your provider compares your results to results from healthy people who are the same height, age, and sex as you. If your results are not normal, it may mean you have a lung condition. Lung function tests cannot diagnose which specific lung disease you have. Obstructive lung conditions cause your airways to become narrow, making it hard for air to flow out of your lungs. Restrictive lung conditions decrease the amount of air your lungs can hold.
Who should not have pulmonary function tests?
The test should not be given to a person who has experienced a recent heart attack, has certain other types of heart disease, or has had a recent collapsed lung.
How does a direct primary care or concierge doctor fit in?
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance.
Sources
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
