Diagnosis

No single test can definitively confirm or rule out SLE. A number of tests are required before SLE can be diagnosed definitively. The first symptoms of SLE can resemble one of many syndromes or disorders, including rheumatoid arthritis, Still's disease, rheumatic fever, Lyme disease, multiple sclerosis, thrombotic thrombocytopenia purpura, cryoglobulinemia, Weber-Christian disease, viral infections, vasculitis, psychosis, and other conditions. Other autoimmune disorders, such as Sjogren's syndrome or scleroderma, may even be present at the same time as SLE.

Criteria for Diagnosing System Lupus Erythematosus

1. Characteristic rash across the cheek

Text Continues Below 2. Discoid lesion rash

3. Photosensitivity

4. Oral ulcers

5. Arthritis

6. Inflammation of membranes in the lungs, the heart, or the abdomen

7. Evidence of kidney disease

8. Evidence of severe neurologic disease

9. Blood disorders, including low red and white blood cell and platelet counts

10. Immunologic abnormalities

11. Positive antinuclear antibody (ANA)

Note: Four of the criteria must be experienced by a patient before a classification of SLE can be made. These criteria, proposed by the American College of Rheumatology, are not to be relied upon solely for diagnosis, however.

Ruling out Other Conditions

The doctor should first rule out common conditions that might be causing the symptoms. The doctor may test the synovial fluid (the lubricating liquid surrounding joints) to rule out rheumatoid arthritis, which is also an autoimmune disease and can occur with SLE. Certain eye and saliva tests may be used if Sjögren's syndrome is suspected.