Types of Lung Function Tests

Lung function tests, which are also known as pulmonary function tests (PFTs), are tests used to check if your lungs are functioning properly. Lung function tests are often used to check for chronic conditions, such as asthma, chronic obstructive pulmonary disease (COPD), and emphysema. These tests are also used to see if lung disease treatments are working. Here we’ll outline the different types of lung function tests, how to prepare for them, and how you can interpret the results. 

What Are the Different Types of Pulmonary Function Tests?

There are several different types of lung function tests, including:

  • Spirometry. This is the most common type of lung function test. It measures how much and how quickly you can move air in and out of your lungs.
  • Lung volume test. Also known as plethysmography, this test measures the amount of air your lungs can hold and the amount that’s left after you exhale as much as you can.
  • Gas diffusion test. This test measures how oxygen and other gasses move from your lungs to the bloodstream.
  • Exercise stress test. This test looks at how exercise affects your lung function.
  • FeNO test. This test measures how much nitric oxide is in the air you breathe out. To get the measurement, you blow slowly and steadily into a device. It’s used with people who have certain types of asthma to see if there’s any inflammation in the lungs and how well steroids are working to control it.
  • Pulse oximetry. This test uses a device that measures how much oxygen your red blood cells are carrying. The device is typically clipped to your fingertip, but it can also be attached to your ears, nose, foot, or toes. 
  • Peak flow measurement. This uses a small plastic device to see how much air you can blow out of your lungs. In this test, you take a deep breath and breathe out as hard and fast as you can. Used mostly on people with asthma, this test can give you advance warning of an asthma attack.
  • Pulmonary angiogram. This is a type of CT scan that focuses on your pulmonary arteries, which are the vessels that connect your heart and lungs. It’s used to detect a potentially life-threatening clot in your lungs called a pulmonary embolism. 
  • Pleural biopsy. Fluid can build up in the tissue that surrounds your lungs and pleura and can cause health problems. For this test, your doctor inserts a needle to get a sample of the pleura tissue.
  • Bronchoscopy. In this test, your doctor will slide a small tube with a camera attached into your airways. The camera lets your doctor see things in your air passages, such as mucus, blood, or tumors. 

Preparing for a Lung Function Test

When preparing for a lung function test, you’ll need to take some steps to make sure your breathing is normal and unrestricted. It’s important to talk with your doctor about what you need to do to prepare for your test. Some of the things you may be asked to do include:

  • Not smoking for six hours before the test
  • Avoiding food or drinks with caffeine
  • Wearing loose, comfortable clothing
  • Avoiding heavy exercise for six hours before the test
  • If you wear dentures, you’ll need to wear them during the test. They’ll help you form a tight seal around the mouthpiece.
  • If you use a short-acting inhaler that’s used only as needed, don’t use it for six to eight hours before your test, if possible.
  • Not eating a heavy meal before the test
  • Taking your daily medications prior to testing unless told otherwise

Interpreting Lung Function Tests

After your test, you can return to your normal daily activities. Normal values are calculated based on your age, height, and gender. If a value is abnormal, a lung problem may be present. Sometimes a patient with normal lungs may have a breathing test value that’s abnormal. Your doctor will explain what your test results mean. 

Take Charge of Your Lung Health

Pulmonary function tests are the best way to determine if there are problems in your lungs. If you think that you may be experiencing lung problems, make sure you talk with your doctor. Connect with a respiratory care provider from Baptist Health if you’re seeking care or treatment in Kentucky or Southern Indiana.


Next Steps and Useful Resources:

5 Tips for Improving Lung Health
How to Help Prevent Lung Cancer by Reducing Your Risk
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