Glossary

Navigating the world of pulmonary fibrosis can feel like drowning in an alphabet soup of medical terms, acronyms, and complex jargon. Our glossary is here to help! We’ve gathered the most common terms and explained them in clear, simple language, so you can focus on what truly matters, understanding your health and feeling empowered in your PF journey.

  • a

  • A sudden worsening of the disease that leads to a significant decline in lung function. The causes may be known or unknown.
  • The air sacs in the lungs where oxygen enters the bloodstream and carbon dioxide leaves the bloodstream.
  • A medical test that shows the amount of oxygen and carbon dioxide in the blood.

  • b

  • A lung biopsy is a test that involves taking a small piece of lung tissue for examination. This can be done during a bronchoscopy by a pulmonologist using a special biopsy needle or forceps, which are passed through the bronchoscope. Alternatively, a surgeon may perform the biopsy during a procedure called video-assisted thoracic surgery (VATS), which allows for obtaining larger tissue samples if needed. VATS is a minimally invasive technique that involves inserting a tiny camera and surgical tools through small incisions in the chest wall. The collected tissue samples are then examined under a microscope to assist in making an accurate diagnosis.
  • Bronchoscopy is a medical test in which a physician inserts a small, flexible lighted tube called a bronchoscope through the mouth or nose and into the trachea and lungs. This procedure allows the physician to directly examine the airways and obtain specimens for diagnosing infections and structural abnormalities. It can also facilitate the collection of small lung tissue samples through a transbronchial lung biopsy, aiding in the diagnosis of various lung diseases and related symptoms.

  • c

  • An “ILD Center of Excellence” is a medical care center that employs a multidisciplinary approach to diagnosis and treatment for patients with interstitial lung diseases (ILD). They bring together healthcare providers from various specialties to offer coordinated, high-quality care to patients.
  • An imaging test that uses X-rays to look at the structures and organs in the chest. It can help healthcare providers identify abnormalities to aid in diagnosis of disease or illness.
  • A disease or medical condition that is simultaneously present with another or others in a person.
  • A group of diseases that can be genetic or autoimmune. CTD is a group of disorders involving the tissue that support organs and other parts of the body. These disorders often involve joints, muscles and skin but can also involve the eyes, heart, lungs, kidneys, and blood vessels. There are more than 200 disorders that affect connective tissue.
  • A medical device that uses mild air pressure to help keep the airways open, and is typically used to treat sleep-related breathing disorders such as sleep apnea.
  • A diagnostic exam that uses X-rays to create cross-sectional images.  For those with lung issues, the patterns in the images can help identify the type and extent of lung diseases.

  • d

  • A group of disorders characterized by fibrosis or scarring in the lungs, another name for interstitial lung disease (ILD).
  • DLCO is a measure of the efficiency of lung gas transfer. Also known as diffusing capacity or transfer factor of the lung for carbon monoxide (CO), it measures the extent to which oxygen passes from the air sacs of the lungs into the blood.
  • Equipment and supplies ordered by health care providers for everyday or extended use. This equipment can include oxygen equipment, wheelchairs, blood testing strips and other equipment as described by health care plans.
  • A medical term that describes shortness of breath

  • e

  • A medical term that describes an increase in the severity of symptoms. The onset may be rapid, called an acute exacerbation. The causes may be known or unknown.

  • f

  • The relationship between FEV1 and FVC. A typical normal value is 70% or higher, though this varies with age.
  • The term used to describe the growth of fibroblasts, a type of cell that contributes to the formation of connective tissue. An increase in growth can result in fibrous scar tissue.
  • A medical term for wound healing in which scar tissue replaces normal tissue to the extent that it can lead to extensive tissue remodeling and the formation of scar tissue..
  • The average rate of flow during the middle half of the FVC test.
  • A measure of how much air a person can exhale during a forced breath. The amount of air exhaled is usually measured during the first, second, or third seconds (FEV1, FEV2, FEV3) of a breath during a medical test called spirometry. Sometimes the FEV6 (at 6 seconds) is used as an alternative to the FVC test.
  • A measure of the total amount of air forcibly exhaled after taking as deep a breath as possible. Forced vital capacity is an important measurement of lung function obtained during spirometry testing.
  • The amount of air left in lungs after exhaling normally.

  • g

  • A condition in which a person’s stomach contents flow backward into the esophagus and throat causing heartburn and other potential issues, sometimes called acid reflux disease or shortened to “reflux”.

  • h

  • A type of mechanical ventilation that uses fluctuating variations of pressure at very high rates
  • A special kind of CT scan that is higher resolution, showing a more detailed image of the lung tissue. HRCT can help detect lung disease by identifying patterns of abnormalities.
  • A healthcare option for patients with a terminal illness that provides physical, social, emotional, and spiritual needs outside of a hospital setting, often at home. Hospice care is a supportive comfort program for individuals near the end of life that have discontinued treatment to cure their disease.
  • A condition where the oxygen level in a person’s blood is low. Hypoxemia is not an illness or condition it is a sign or symptom of a problem with breathing or blood flow.
  • A condition where the oxygen level in a person’s tissues is low that is caused when the blood does not carry adequate amounts of oxygen from the lungs to the rest of the body.

  • i

  • A description of a disease or condition whose cause is unknown.
  • A medical term to describe interstitial lung diseases that have no known cause. Idiopathic pulmonary fibrosis (IPF) is a type of IIP.
  • A specific serious chronic long term disease that affects the tissue surrounding the air sacs, or alveoli, in the lungs. This condition develops when the lung tissue becomes  thick and stiff for unknown reasons.
  • ILD is an umbrella term used for a large  group of diseases that cause scarring (fibrosis) of the lungs. This scarring causes stiffness in the lungs which makes it difficult to breathe and get oxygen to the bloodstream.
  • The space around the alveoli in the lung.

  • l

  • Liters per minute is the measurement of how much oxygen flows from an oxygen delivery device, such as a home oxygen concentrator. Note: the numerical setting on a portable oxygen concentrator (POC) medical device is not liters per minute; the number indicates only a low, medium, or high setting of the device.

  • m

  • The total amount of air moved in or out of the lungs in one minute.

  • o

  • A colorless, odorless, tasteless gas that is about 21 percent of the atmosphere or air we breathe necessary for support of life.
  • A medical device that draws in the surrounding air and filters out nitrogen. This process increases the concentration of oxygen in the air it delivers through a tube.

  • p

  • A healthcare option that focuses on management and relief from pain and other symptoms of an illness. Palliative care aims to provide comfort and  improve quality of life for people and their families. This care is offered in coordination with curative treatments and does not depend on if the condition can be cured. Note: This is not the same as hospice care.
  • The fastest rate that you can force air out of your lungs.
  • A medical device that is a small light-weight oxygen concentrator that is intended to be carried or pulled. It can be operated by a battery or plugged in. Note: the numerical setting on a portable oxygen concentrator (POC) medical device is not liters per minute; the number indicates only a low, medium, or high setting of the device.
  • A medical term that means relating to or occurring in the lungs.
  • A type of high blood pressure that is located in the pulmonary arteries.
  • A condition that occurs when the lung tissue becomes damaged and scarred, which makes it difficult for the lungs to work properly to supply the body with oxygen. Pulmonary fibrosis may occur as a result of many different diseases or the cause may be unknown.
  • A test that measures how well a person’s lungs are working. Measuring lung volume, capacity, rates of flow and gas exchange. Pulmonary function tests are non-invasive and can be completed in a doctor’s office utilizing a variety of equipment.
  • A condition that affects the blood vessels in the lungs, causing abnormally high blood pressure in the arteries in the lungs.  PH makes the heart work harder than normal to pump blood into the lungs and can damage the heart and cause shortness of breath, chest pain, and lightheadedness.

  • r

  • A physician specializing in using radiology tests to diagnose illness.
  • The amount of air left in the lungs after exhaling as much as you can.
  • A physician whose specialty is the diagnosis and treatment of diseases such as arthritis and other autoimmune and inflammatory diseases of the joints, muscles, and bones.

  • s

  • A form of interstitial lung disease linked to scleroderma, where inflammation and scarring develop in the lungs, making it harder to breathe and for oxygen to move into the bloodstream.
  • A chronic autoimmune disease that causes the body to produce too much collagen, which can lead to thickening or tightening of the skin and may also affect internal organs such as the lungs, digestive system, heart, and kidneys.
  • The six-minute walk test (6MWT) is a simple cardiopulmonary function test used by healthcare providers to assess exercise tolerance. It measures how far a person can walk in six minutes. This test is also useful for determining the need for supplemental oxygen and the appropriate flow rate (liters per minute) required during exertion.
  • A chronic autoimmune condition in which the immune system attacks moisture-producing glands, most commonly causing dry eyes and dry mouth. It is a systemic disease that can also affect other parts of the body, including the lungs, joints, and nervous system.
  • A disorder in which breathing repeatedly stops and starts while a person is sleeping. Sleep apnea sometimes occurs along with pulmonary fibrosis.
  • A lung test that assesses the integrated mechanical function of the lung, chest wall, respiratory muscles and airways. Spirometry measures the amount of air inhaled and exhaled over time.
  • A medical term that describes the phases in progressive disease. There is no universally accepted agreement on the stages of pulmonary fibrosis. Some doctors describe the progression as mild or early, moderate, severe, or advanced.

  • t

  • The amount of air inhaled or exhaled during normal breathing.
  • The total volume of the lungs when filled with as much air as possible.

  • v

  • The total volume of air that can be exhaled after inhaling as much as you can.

  • x

  • A type of radiation that can be used for medical purposes.  Many diagnostic exams use low doses of X-rays to generate images.
The page was last reviewed on July 20, 2026