In its commitment to serving the PF community, the Pulmonary Fibrosis Foundation provides a detailed explanation of the process for diagnosing PF.
Dr. Lederer divides the diagnostic process into several sections: doctor visit clues, initial diagnostic steps, and establishing disease type.
Doctor Visit Clues
Initial Diagnostic Steps
If these three major clues are present, a doctor will start thinking about PF and order testing. Two tests are lung function and high-resolution CT scan of the chest, which may be ordered at the same time.
1. Spirometry involves breathing through the mouth into a machine that measures air volume and speed of entry and exit when inhaling and exhaling. This is done during both regular breathing and after taking the deepest breath possible and blowing as hard and fast as one can. Three important results on a printout are forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and the FEV1/FVC ratio.
a. “One of the most important measures of disease severity,” FVC is the amount of air blown out after the deepest possible breath, reflecting how much air the lungs can hold. FVC will decrease as scar tissue builds, indicating less lung capacity and greater disease severity. In early disease, a person can have a normal FVC of over 80% of the expected amount for someone the same age and gender with normal lung function. (An example is shown in which a person’s test result in liters of air is just 48% of the reference amount.)
b. FEV1 is the amount of air exhaled in the first second of blowing out as hard and fast as possible, and is often lower than normal in PF. Normal FEV1 is over 80% of the expected amount. (In the example, FEV1 is just 51% of normal and usually close to FVC in a person with PF.)
c. FEV1/FVC ratio is the amount of air exhaled in the first second versus the total amount. Most people with PF have a normal ratio of greater than 70%, where most of the air is exhaled within the first second.
2. Diffusing capacity measures how much air is passing from the lungs into the bloodstream (in other words, how thick the walls of air sacs are inside the lungs). Diffusing capacity decreases as scarring increases since, even in early disease, it becomes harder to get oxygen into blood with air sac walls getting thicker and stiffer. A normal diffusing capacity is 70%-80% of expected value. (It is usually 30%-40% less than FVC in someone with PF.)
Establishing Disease Type—Which Kind of PF?
Dr. Lederer advises this entire process, or at least the later stages, be done by a pulmonologist. A second opinion can be pursued at any of 68 Pulmonary Fibrosis Foundation Care Centers throughout the US.
The webinar can be found at:
The webinar can also be found on YouTube, where slides can be viewed in full screen:
To ask any questions or obtain slides from the presentation, contact the PFF Patient Communication Center at:
firstname.lastname@example.org or toll-free 844.825.5733
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