How Is Sarcoidosis Diagnosed?

Your doctor will find out if you have sarcoidosis by taking a detailed medical history and conducting a physical exam and several diagnostic tests. The purpose is to:

• Identify the presence of granulomas in any of your organs
• Rule out other causes of your symptoms
• Determine the amount of damage to any of your affected organs
• Determine whether you need treatment.

Medical History

Your doctor will ask you for a detailed medical history. He or she will want to know about any family history of sarcoidosis and what jobs you have had that may have increased your chances of getting sarcoidosis.

Your doctor may also ask whether you have ever been exposed to inhaled beryllium metal, which is used in aircraft and weapons manufacture, or organic dust from birds or hay. These things can produce granulomas in your lungs that look like the granulomas that are caused by sarcoidosis but are actually signs of other conditions.

Physical Exam

Your doctor will look for symptoms of sarcoidosis, such as red bumps on your skin; swollen lymph nodes; an enlarged liver, spleen, or salivary gland(s); or redness in your eyes. He or she will also listen for abnormal lung sounds or heart rhythm. Your doctor also will check for other likely causes of your symptoms.

Diagnostic Tests

There is no one specific test for diagnosing sarcoidosis. It is harder to diagnose sarcoidosis in some organs (e.g., heart, nervous system) than in others. Your doctor will probably conduct a variety of tests and procedures to help in the diagnosis.

These include:

• Chest X Ray. A chest x ray takes a picture of your heart and lungs. It may show granulomas or enlarged lymph nodes in your chest. About 95 out of every 100 people who have sarcoidosis have an abnormal chest x ray.
• Doctors usually use a staging system for chest x rays taken to detect sarcoidosis:
  • Stage 0: Normal chest x ray
  • Stage 1: Chest x ray showing enlarged lymph nodes but otherwise clear lungs
  • Stage 2: Chest x ray showing enlarged lymph nodes and shadows in your lungs
  • Stage 3: Chest x ray showing shadows in your lungs, but the lymph nodes are not enlarged
  • Stage 4: Chest x ray showing scars in the lung tissue.
  In general, the higher the stage of the x ray, the worse your symptoms and lung function are. But there are a lot of differences among people. If your x-ray results show Stages 0, 1, 2, or 3, you may not have symptoms or need treatment, and you may get better and have normal chest x rays again over time.
• Blood Tests. These tests can show the number and type of cells in your blood. They also will show whether there are increases in your calcium levels or changes in your liver, kidney, and bone marrow that can occur with sarcoidosis.
• Lung Function Tests. One test uses a spirometer (spi-rom'e-ter), a device that measures how much and how fast you can blow air out of your lungs after taking a deep breath. If there is a lot of inflammation and/or scarring in your lungs, you will not be able to move normal amounts of air in and out.
• Another test measures how much air your lungs can hold. Sarcoidosis can cause your lungs to shrink, and they will not be able to hold as much air as healthy lungs.
• Electrocardiogram (EKG). This test will help show if your heart is affected by sarcoidosis.
• Pulse Oximetry. A small clip attached to your finger tip can show how well your heart and lungs are moving oxygen into your blood.
• Arterial Blood Gas Test. This test is more accurate than pulse oximetry for checking the level of oxygen in your bloodstream. Blood is taken from an artery (usually in your wrist). It is then analyzed for its oxygen and carbon dioxide levels.
• Fiberoptic Bronchoscopy. In this procedure, your doctor inserts a long, narrow, flexible tube with a light on the end through your nose or mouth into your lungs to look at your airways. This tube is called a bronchoscope. You most likely would have this procedure as an outpatient in a hospital under local anesthesia.
• Bronchoalveolar Lavage (brong"ko-al-ve'o-lar lah-vaje') (BAL). During bronchoscopy, your doctor may inject a small amount of salt water (saline) through the bronchoscope into your lungs. This fluid washes the lungs and helps bring up cells and other material from the air sacs deep in your lungs where the inflammation usually starts to develop. The cells and fluid are then examined for signs of inflammation.
• Biopsy. Your doctor may take a small sample of tissue from one of your affected organs. For example, when breathing tests or chest x rays show signs of sarcoidosis in your lungs, your doctor may do a fiberoptic bronchoscopy biopsy. This will help confirm the diagnosis. Your doctor inserts a tiny forceps through the bronchoscope to collect tissue that will be examined. Because the granulomas may be spread out in your lungs, the bronchoscope may miss some of them.
• Biopsies of your skin and liver are sometimes done to detect granulomas in these organs.
• You may have sarcoidosis in other organs as well and multiple biopsies may be necessary. However, every organ involved does not need to be biopsied for a diagnosis to be made.
• Computerized Tomography (CT) Scan. This test provides a computer-generated image of your organs that has more detail than a regular chest x ray. It can provide more information about how sarcoidosis has affected an organ.
• Your doctor may do a CT scan to:
  • Obtain more information about how much of your lung is affected by sarcoidosis.
  • Detect sarcoidosis in your liver. A CT scan of your abdomen will show if your liver is enlarged and if there is a pattern suggesting granulomas.
• Magnetic Resonance (MR) Scan. This test is also called nuclear magnetic resonance (NMR) scanning or magnetic resonance imaging (MRI). This scan uses powerful magnets and radio waves to make images of some of your organs that your doctor doesn't want to risk doing a biopsy on. For example, an MR scan can be used to diagnose sarcoidosis in your brain, spinal cord, nerves, or heart.
• Thallium and Gallium Scans. These scans are often done to see if sarcoidosis is affecting your heart. Thallium and gallium are radioactive elements. Your doctor injects a small amount of one of them into a vein in your arm. The elements collect at places in your body where there is inflammation. After awhile, your body is scanned for radioactivity. Increased radioactivity at any place may be a sign of inflammation.
• This test gives information on the tissue in your body that has been affected by sarcoidosis and the amount of damage to it. But since this test shows all inflammation in your body, even inflammation caused by conditions other than sarcoidosis, it does not give a definite diagnosis of sarcoidosis.
• Positron Emission Tomography (PET) Scan. This test also uses radioactive injections. It may be more sensitive than gallium in detecting areas of inflammation. Some doctors are using it instead of gallium scans.

Your doctor may not need to find every one of your organs affected by sarcoidosis, only those that cause symptoms. Often the organs affected by the condition continue to function well and don't need to be treated.