Stages of Pulmonary Fibrosis | American Lung Association

This website uses cookies. By continuing you are agreeing to our privacy policy.

Stages of Pulmonary Fibrosis

Pulmonary fibrosis often gets worse over time. No one can predict how fast a patient's PF will progress. In some people, PF progresses very quickly while others live with the disease for many years.

How Is Pulmonary Fibrosis Staged?

When someone is diagnosed with pulmonary fibrosis, it is normal to wonder: how advanced is the disease? There is no formal staging system for pulmonary fibrosis. Physicians use different factors, like the ones listed below, to describe the disease as mild, moderate, severe or very severe:

  • Symptoms: Discussing symptoms with your doctor is key to determining the severity of your PF. You might be asked about how frequently you become breathless or how often you cough. Worsening breathlessness and cough don't always mean the disease has progressed. But knowing your symptoms helps your doctor better understand your particular disease.
  • Pulmonary Function Tests (PFTs) or Lung Function Tests give your doctor important information about the amount of air the lungs can hold and how forcefully you can empty air from the lungs. A PFT reveals your forced vital capacity (FVC) which is the amount of air that is exhaled starting from a maximal inhalation. This percentage can help your physician understand if you have mild, moderate, severe or very severe PF. The most basic test is spirometry.
  • A six-minute walk test may be done to measure your exercise capacity.
  • A high-resolution CT scan (HRCT) shows how much scarring is in the lungs.

A scoring system was recently developed called the GAP Model which uses Gender, Age and Physiology (and includes your FVC score and diffusing capacity) to stage PF. Not all physicians use this staging system. Science is always advancing so ask your doctor to explain your stage and the tests you may need.


    Reviewed and approved by the American Lung Association Scientific and Medical Editorial Review Panel. Last reviewed January 17, 2018.

    Page Last Updated: March 13, 2018

    Sign up for updates

    Stay up to date on the latest news and information on the fight against pulmonary fibrosis.

    Red button with telephone
    Ask An Expert

    Questions about your lung health? Need help finding healthcare? Call 1-800-LUNGUSA.

    Get help
    Red button of two hand prints
    We need your generous support

    Make a difference by delivering research, education and advocacy to those impacted by lung disease.

    Button of turquoise LUNG FORCE swirl
    What is LUNG FORCE?

    LUNG FORCE unites women and their loved ones across the country to stand together in the fight against lung cancer.

    Get involved
    Join the fight for healthy lungs and healthy air.
    Donate Now.