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Diagnosis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) can be difficult to diagnose because:

  • Symptoms are similar to many other diseases
  • There is no single test to identify SLE
  • Symptoms can vary because SLE can affect different areas of the body in different people or at different times in the same person

SLE may be suspected if at least 4 of the following signs are present with no other apparent reason:

  • Butterfly facial rash over the cheeks and bridge of the nose—considered a hallmark sign of SLE
  • Presence of discoid lupus erythematosus—chronic rashes, especially on the face and scalp, which can lead to scarring (discoid lupus often leads to SLE)
  • Skin photosensitivity (easily burned by the sun)
  • Ulcers in the mouth or above the back of it
  • Arthritis—swelling, pain, and/or warmth in at least 2 limb joints
  • Inflammation of the lining of the heart (pericarditis) or lungs (pleuritis)
  • Abnormal kidney tests
  • Seizures or psychosis
  • Anemia—abnormally low number of blood cells
  • Presence of antinuclear antibodies
  • Evidence of immune dysfunction

Changes in the blood and kidney may be discovered through:

Blood Tests

SLE can cause a variety of changes in the blood that can be different from person to person. Some factors that will be looked for include:

  • Presence of antinuclear antibodies (ANA)—Specific antibodies that attack the contents of your body's cells. These antibodies are believed to be associated with SLE and nearly all people with SLE will test positive.
  • Other evidence of inflammation
  • Abnormalities on CBC—Measure of all the blood cells.
  • Screen for substances normally filtered out through the kidneys, which shows changes to kidney function

Urine Tests

Presence of proteins, blood, or other substances in the urine may indicate changes in kidney function.


Guidelines for referral and management of systemic lupus erythematosus in adults. American College of Rheumatology Ad Hoc Committee on Systemic Lupus Erythematosus Guidelines. Arthritis Rheum. 1999;42(9):1785-1796.

How is lupus diagnosed? Lupus Foundation of America website. Available at: Updated July 25, 2013. Accessed May 16, 2016.

Lupus. National Institute of Arthritis and Musculoskeletal and Skin Diseases website. Available at: Updated February 2015. Accessed May 16, 2016.

Systemic lupus erythematosus (SLE). EBSCO DynaMed Plus website. Available at: Updated September 15, 2016. Accessed October 6, 2016.

Systemic lupus erythematosus (SLE). Merck Manual Professional Version website. Available at: Updated June 2013. Accessed May 16, 2016.