Cystic fibrosis (CF) progression can be measured in a number of ways. Below are some of the most common tests that can help determine the impact and progression of CF.
Measuring Disease Impact
One of the most common tests used to measure CF progression is a pulmonary function test, of which one component is FEV1, or forced expiratory volume in 1 second. This is done during the spirometry test. The FEV1 test is usually done after age 6.
But FEV1 does not always change at the beginnings of lung damage and disease progression. There are other tests that may find lung damage and disease progression earlier.
Computed tomographic (CT) scans
A CT scan is an x-ray technique that shows much greater detail by using multiple images of a body part, put together by a computer, to form a detailed image. Since it takes a photo of the lungs, damage may be visible early on.
Magnetic resonance imaging (MRI)
An MRI produces images of specific body parts, similar to x-rays and CT scans, but without the exposure to radiation. The use of MRI testing in people with CF continues to evolve, which leads to more accurate test results. It's important to keep in mind that MRI is today considered a research tool.
Lung clearance index (LCI)
LCI is a test that is sometimes used during clinical trials of CF medicines. It measures how much air is getting to all the different parts of the lungs when someone breathes. It is considered to be more sensitive than the FEV1 test, so in the early stages of lung disease it may catch early progression sooner.
Other tests besides FEV1 can be used in order to detect early lung damage.
Because FEV1 doesn't always find progression when it begins, healthcare providers may also look to other tests to assess lung function.