If you’re talking to your doctor about pulmonary function testing, it helps to know key terms. This glossary contains some common words your doctor may use when talking about lung disease and tests for lung function.

Download Glossary of Pulmonary Function Terms as a PDF.


Alpha-1 Antitrypsin Deficiency – A genetic condition that can affect all age groups. It may lead to emphysema at an early age (30-40 years old).

Alveoli or Air Sacs – Microscopic grape-like structures in the airways of your lungs. Gas exchange takes place in these air sacs.

American Thoracic Society (ATS) – Society of doctors and other healthcare workers who work to advance the science of lung health. ATS sets standards for testing pulmonary (lung) function.

Anemia – When you don’t have enough red blood cells and hemoglobin (a protein that carries oxygen) in your blood.

Arterial Blood Gases (ABGS) – Sample of blood drawn from an artery, most often near the wrist. This measures acid-base balance (pH), carbon dioxide (PaCO2), oxygen (PaO2), and oxygen saturation (SaO2).

Asbestosis -Lung  disease that can develop after inhaling asbestos fibers. It may cause scar tissue to surround the lungs.

Bronchodilator – Medicine that dilates or opens up the airways in your lungs. You may get it from a nebulizer, inhaler, or oral pill.

Carbon Dioxide (PaCO2) – Amount of carbon dioxide in your arterial blood. Carbon dioxide is a normal by-product of the body. You exhale it from your body when you breathe.

Congestive Heart Failure (CHF) – Excessive fluid buildup in the body due to heart weakness. It can make you feel like you’re out of breath.

Emphysema – Airway disease in which the walls of the alveoli (air sacs) are damaged or destroyed.

Farmer’s Lung – Lung disease caused by breathing in wet hay or molds.

Flow Volume Curve or Loop – Graph plotting the flow (speed) and volume at which you breathe in and out during the FVC test.

Obstructive Lung Disease/COPDChronic disease that makes it hard to exhale or breathe out. These include emphysema, chronic bronchitis, and asthma.

Oxygen (PaO2) – Amount of oxygen in your arterial blood.

Oxygen Saturation (SaO2) – Percent of hemoglobin in red blood cells carrying oxygen.

Pulmonary – Anything that involves your lungs.

Pulmonary Fibrosis – Lung disease caused by scar tissue in the lungs.

Red Blood Cell (RBC) – Blood cell that contains hemoglobin. RBCs carry oxygen in your blood.

Restrictive Lung Disease – Disease that makes it hard to inhale, or breathe in. These include asbestosis, farmer’s lung, and fibrosis.

Want to learn more?

For more in-depth information on this topic, please visit the Big Fat Reference Guide (BFRG). If you are enrolled in AlphaNet’s Subscriber Portal, you can access the BFRG here.

Download Glossary of Pulmonary Function Terms as a PDF.


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