Sarcoidosis, how is is diagnosed?

How Is Sarcoidosis Diagnosed?

Your doctor will diagnose sarcoidosis based on your medical history, a physical exam, and the results from tests. He or she will look for granulomas (inflamed lumps) in your organs. Your doctor also will try to rule out other causes of your symptoms.

Medical History

Your doctor may ask you detailed questions about your medical history. For example, he or she may ask whether you have a family history of sarcoidosis. Your doctor also may ask whether you've had any jobs that may have raised your risk for the disease.

Your doctor also may ask whether you've ever been exposed to inhaled beryllium metal. This type of metal is used to make aircrafts and weapons. Your doctor also may want to know whether you've had contact with organic dust from birds or hay.

Exposure to these substances can cause inflamed lumps in your lungs that look like the granulomas from sarcoidosis. However, these lumps are signs of other conditions.

Physical Exam

Your doctor will examine you for signs and symptoms of sarcoidosis. Signs and symptoms may include red bumps on your skin; swollen lymph nodes; an enlarged liver, spleen, or salivary glands; or redness in your eyes. He or she will check for other causes of your symptoms.

Your doctor also may listen to your lungs and heart. Abnormal breathing and heartbeat sounds may be a sign that sarcoidosis is affecting your lungs or heart.

Diagnostic Tests

You may have tests to confirm a diagnosis and to find out how the disease is affecting you. Tests include chest x ray, lung function tests, biopsy, and other tests to assess organ damage.

Chest X Ray

A chest x ray is a painless test that creates pictures of the structures inside your chest, such as your heart and lungs. The test may show granulomas or enlarged lymph nodes in your chest. About 95 percent of people who have sarcoidosis have an abnormal chest x ray.

Lung Function Tests

Lung function tests measure the size of your lungs, how much air you can breathe in and out, how fast you can breathe air out, and how well your lungs deliver oxygen to your blood. These tests may be used to find out whether sarcoidosis is affecting your lungs.

Biopsy

Your doctor may do a biopsy to confirm a diagnosis or rule out other causes of your symptoms. A biopsy involves taking a small sample of tissue from one of your affected organs.

Usually, doctors try to biopsy the organs that are easiest to access. Examples include the skin, tear glands, or the lymph nodes that are just under the skin.

If this isn't possible, your doctor may use a positron emission tomography (PET) scan to pinpoint areas for biopsy. For this test, a small amount of a radioactive substance is injected into a vein, usually in your arm.

The substance, which releases energy, travels through the blood and collects in organs or tissues. Special cameras detect the energy and convert it into three-dimensional pictures.

If lung function tests or a chest x ray shows signs of sarcoidosis in your lungs, your doctor may do a bronchoscopy (bron-KOS-ko-pee) to get a small sample of lung tissue.

During this procedure, a thin, flexible tube is passed through your nose (or sometimes your mouth), down your throat, and into the airways to reach your lung tissue. (For more information, see "What To Expect During Bronchoscopy.")

Other Tests To Assess Organ Damage

You also may have other tests to assess organ damage and find out whether you need treatment. For example, your doctor may recommend blood tests and/or an EKG (electrocardiogram).

Everyone who is diagnosed with sarcoidosis should see an ophthalmologist (eye specialist) for eye tests, even if they don't have eye symptoms. This is important because eye damage can occur without symptoms.