To diagnose pneumonitis, your doctor or other healthcare professional reviews your medical history and family history. You talk about your symptoms and review any medicines you take and previous treatments such as cancer treatment that you've had. You also will likely be asked about any ongoing or repeated contact with dusts, chemicals, birds and mold sources, especially through home, work or hobbies.
The healthcare professional does a physical exam and uses a stethoscope to listen to your lungs while you breathe.
One option to help diagnose hypersensitivity pneumonitis is to avoid the suspected environmental substance for several weeks to see if symptoms get better.
To tell pneumonitis from other lung conditions, you'll likely have one or more tests.
Blood tests
Certain blood tests can be useful to pinpoint a diagnosis. For example, a blood test may be able to tell if you have an infection. Blood tests can check for antibodies that suggest exposure to an allergen. Another blood test, called an arterial blood gas, can measure the oxygen and carbon dioxide levels in the sample.
Imaging tests
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Chest X-ray. Images of your lungs can give an idea of where and how severe the inflammation is. An X-ray also may rule out other conditions that are causing your symptoms, such as pneumonia. Sometimes an X-ray may not show any changes.
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Computerized tomography (CT).
A
CT
scan combines X-ray images taken from many different angles to create images of structures inside the body. A
CT
scan gives much greater detail of changes in your lungs than a chest X-ray can show. A
CT scan also can be helpful in finding out how much lung damage has occurred.
Pulmonary function tests
Pulmonary function tests are done to find out how well your lungs are working:
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Spirometry. In this test, you breathe out quickly and forcefully through a tube connected to a machine. The machine measures how much air the lungs can hold and how quickly air moves in and out of the lungs.
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Lung volume test. This test measures the amount of air the lungs hold at different times when breathing in and out.
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Lung diffusion test. This test shows how well the body moves oxygen and carbon dioxide between the lungs and the blood.
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Pulse oximetry. This simple test uses a small device placed on one of the fingers to measure how much oxygen is in the blood. The percentage of oxygen in the blood is called oxygen saturation. Your healthcare professional may recommend a six-minute walking test with a check of your oxygen saturation.
Imaging and lung function tests also can be used to check your condition over time and see how treatments are working.
Bronchoscopy
A bronchoscopy is a procedure to look at your lungs and air passages. A thin tube called a bronchoscope is passed through your nose or mouth, down your throat and into your lungs.
Your doctor may flush a section of your lung with a saltwater solution to collect lung cells and other materials. This flushing procedure is known as a lavage.
Your doctor also may remove very small tissue samples from your lungs. The tissue samples are sometimes too small to make the right diagnosis. But this form of biopsy also may be used to rule out other conditions.
Surgical lung biopsy
Your doctor may want to examine larger samples of tissue from several sites in your lungs that can't be reached using bronchoscopy. A surgical procedure to collect these samples may be needed. Although a surgical biopsy is invasive and has a risk of complications, it may be the only way to make the right diagnosis. This procedure may be done as a minimally invasive surgery.