Healthy Living

How Is Sarcoidosis Diagnosed?

How Is Sarcoidosis Diagnosed?

What is sarcoidosis?

Sarcoidosis is an inflammatory disease, which is characterized by the growth of granulomas or tiny collections of inflammatory cells in various parts of the body. When the immune system is slowed down and when these numerous clumps form, they tend to interfere with the organ’s proper functioning and structure. When sarcoidosis is left unchecked, it would result in chronic inflammation leading to fibrosis, which is the scarring and thickening of connective tissues. 

This inflammatory disorder can affect different organs in the body, which include the muscles, bones, eyes, sinuses, brain, skin, heart, kidneys, liver, and other areas. However, most of the time, sarcoidosis targets the lymph nodes and lungs. Around 90 percent of individuals who are diagnosed with the disease usually have lung involvement, and when the disease affects the lungs, it is regarded as pulmonary sarcoidosis.

Causes and Risk Factors

Doctors are still unable to identify the exact cause of this medical condition. However, race, gender, and genetics may increase the risk of developing this condition.

Sarcoidosis is more commonly seen in women than men. Moreover, individuals who have a family history of sarcoidosis usually have a higher risk of getting this illness as well as those who have African-American descent.


Doctors primarily rule out other possible medical conditions before confirming that the symptoms you are experiencing are due to sarcoidosis. In medical terms, this process is called as “diagnosis of exclusion”.  The disease also produces just a few symptoms during its early stage, and when individuals experience any symptoms, they are often similar to other disorders.  

The doctor would initially start with a physical examination, which would include a close examination of any kind of skin lesions. The doctor would also check the following: 

  • Skin bumps or rashes
  • Lymph node swelling
  • Enlarged liver or spleen
  • Heart and lung sounds

Certain tests provide important and additional information about your condition. Since the symptoms of sarcoidosis often mimic the symptoms of other diseases, the doctor needs to rule out other possible causes. Below are certain tests used by doctors to diagnose sarcoidosis:

1. Chest X-ray

A chest X-ray would provide a clear picture of the heart, lungs, and the surrounding lymph nodes. It also helps in revealing where the infection-fighting white blood cells are formed, which is often considered as the primary indication of sarcoidosis and other medical conditions. It also helps by showing lung damage caused by the disease.

There are basically five patterns of chest X-rays, and the results fall into any of the patterns. However, one should note that these patterns do not represent the stages of the disease, but rather only allow doctors to classify the disease. 

  • 0= Represents a normal chest X-ray
  • I = Bilateral hilar lymphadenopathy or BHL. This pattern is a common sarcoidosis presentation. There is equal enlargement of the lymph nodes at the root of the lungs on both sides. 
  • II = BHL pulmonary infiltrates. It shows a disease process that expands into and throughout other lung tissues. 
  • III = Pulmonary infiltrates without BHL. This X-ray pattern would represent a disease process that is spread throughout the tissues of the lungs but without signs of lymph node enlargement.
  • IV = Extensive Pulmonary fibrosis. This pattern displays a small lung field and scarring or a retraction of both the hila. If this pattern is shown on an X-ray, then it is an indication that this type of disease is one of the most severe ones. It can also be a permanent type of disease.

2. CT Scan or Computerized Tomography

A CT scan is another form of X-ray that helps in providing more detailed images of the lungs and lymph glands than a routine chest X-ray. A CT scan does not hurt and would simply involve lying down on a table for approximately 10-15 minutes.

3. Mediastinoscopy

It is a surgical procedure, which involves a small incision in the neck above the breastbone, wherein a thin scope is placed in the opening. The doctor collects a tissue sample through the scope. The tissue sample is further examined under a microscope to identify lung problems. 

4. Bronchoscopy

This procedure would involve passing a small tube called a bronchoscope down the trachea and into the bronchial tubes. This procedure is performed to diagnose airway problems and to take tissue samples to look for granulomas. Bronchoscopy is an outpatient procedure and is quite safe with very low risks. It also provides the doctor a chance to arrive at an accurate diagnosis.

Before the test, the doctor would ask you not to consume any food or drinks at least eight hours prior to the procedure. Certain medications will be given to you to make you feel relaxed. Since these medications have the tendency to make you feel groggy, it is advisable to have someone accompany you and drive you home after the procedure since you will not be allowed to drive. 

The procedure would mostly last around 15-45 minutes with additional hours given for recovery. The doctor can also perform a bronchoalveolar lavage or air sac biopsy. A biopsy of the lymph nodes can also be performed with the help of a needle that is inserted through the bronchoscope. 

5. Blood Tests

There is no particular blood test to diagnose sarcoidosis. However, certain blood tests can help assess the functioning of the cells by evaluating the number of cells, types of blood cells along with blood proteins in the body. Blood tests can also help determine liver problems and high calcium levels in the body, which at times present in sarcoidosis.

Angiotensin-converting enzyme (ACE) is a substance produced in large amounts by the cells that form granulomas. This substance can be measured using a blood test. However, high ACE levels do not necessarily indicate sarcoidosis since increased levels of ACE are also seen in patients who have other diseases. Moreover, patients with sarcoidosis do not always have increased ACE levels. Thus, there are no specific blood tests when it comes to diagnosing sarcoidosis. 

6. Other Biopsies

If the doctor suspects skin lesions or bumps that may be related to sarcoidosis, tissue samples may be taken and then sent to the laboratory for further examination. Sometimes, lymph nodes can also be used for biopsy.

7. PET Scan

In this particular test, a radioactive material known as F-fluorodeoxyglucose is injected into the veins in small amounts. This particular substance is known to collect in those areas where there is a collection of granulomas in the body. With the help of a scanner, the doctor can then detect as well as record the exact location and amount of inflammation present in the body. This type of scan also helps in detecting inflammation, which has been created by other conditions apart from sarcoidosis. Thus, it can also be used in combination with other forms of testing.

8. Pulse Oximetry

This particular test helps measure the amount of oxygen present in the blood through a sensor, which is attached to the finger of the patient. If the oxygen level tends to go down, then the doctor can recommend using supplemental oxygen.

9. Electrocardiogram

The ECG or EKG is regarded as a routine test that helps check the electrical as well as the muscular functions of the heart. In this particular test, electrodes with adhesive pads are attached to the skin of the patient's chest, arms, or legs. The ECG machine then creates a picture of the various electrical impulses on a graph paper. An ECG is a good screening test to detect any abnormalities present in the heart.

10. Gallium Scan

In this particular procedure, the doctor would inject the radioactive chemical gallium-67 into the vein. The radioactive chemical is collected in the tissues, which have become inflamed. When a body scan is performed, it would indicate the affected tissues and how much of the tissues are affected.

This type of scan would also help in revealing other types of inflammation in the body. However, this test is usually not preferred due to its certain limitations.