When a doctor or other healthcare provider suspects that a patient has ILD, they will collect information about the patient’s medical and personal history, work and home environment, hobbies, and illness that may be present in the family. This can help a doctor identify exposures or other diseases that might have caused lung injury and scarring. The doctor will also often order pulmonary function tests, a chest x-ray, blood work, and a high-resolution CT scan.
Pulmonary function tests measure how much air the lungs can hold, and how the lungs are working overall. Scarring can cause the lungs to shrink, and it can also make them stiff and unable to fully expand. This means the lungs are able to hold less air. Scar tissue may also affect the ability of the lungs to transfer oxygen to the bloodstream.
Blood work (serology) can provide information about exposures that may have caused a person’s lung injury, or show that other diseases are present which may be associated with the development of PF. If a cause for the PF, such as an autoimmune disease or environmental exposure, is identified, then the diagnosis is not IPF.
A high-resolution computed tomography (HRCT) scan is a special type of x-ray that shows fine detail of the lung tissue. On a CT scan (also known as CAT scan) healthy lung tissue looks nearly black, and scar tissue and inflammation appear grey or white. A specific scarring pattern called usual interstitial pneumonia (UIP), can help to diagnose IPF when it is seen on an HRCT scan.
After reviewing the results of all of these tests, a physician can often confirm a diagnosis of IPF. Sometimes more information is needed and a lung biopsy may be performed.