Tests and diagnosis

By Mayo Clinic Staff

Sarcoidosis can be difficult to diagnose because the disease produces few signs and symptoms in its early stages. When symptoms do occur, they vary by organ system affected and can mimic those of other disorders.

Your doctor will likely start with a physical exam, including a close examination of any skin lesions you have. He or she will also listen carefully to your heart and lungs and check your lymph nodes for swelling. Your doctor may also be interested in seeing any previous chest X-rays, to check for signs of early sarcoidosis that may have been overlooked.

Diagnostic tests can help exclude other disorders and determine what body systems may be affected by sarcoidosis. Your doctor may recommend:

  • X-ray, to check for evidence of lung damage or enlarged lymph nodes in your chest. Some people are diagnosed with the condition after chest X-rays taken for other reasons.
  • CT scan, if complications are suspected.
  • PET or MRI, if sarcoidosis seems to be affecting your heart or central nervous system
  • Blood tests, to assess your overall health and how well your kidneys and liver are functioning.
  • Lung function tests, to measure lung volume and how much oxygen your lungs deliver to your blood.
  • Eye exam, to check for vision problems that may be caused by sarcoidosis.


Your doctor may order a small sample of tissue (biopsy) be taken from a part of your body believed to be affected by sarcoidosis to look for the granulomas commonly seen in the condition. Biopsies can most easily be taken from your skin or the outer membrane of your eye. Tissue is sent to a laboratory for analysis.

Lung biopsies or lymph node biopsies can be obtained through a procedure (bronchoscopy) in which a thin, flexible tube containing a camera is inserted down your throat.

Jan. 10, 2013