Lupus is complex and is often difficult to diagnose, as a result there is no single laboratory test that can determine if a person has lupus. To complicate matters, many symptoms of lupus are similar to those of other diseases, and can come and go over weeks and months. It can often take years for a diagnosis to be made. Doctors use the American College of Rheumatology's “Eleven Criteria of Lupus” to help make—or exclude—a diagnosis of lupus. Typically, four or more of the following criteria must be present to make a diagnosis of systemic lupus. The “Eleven Criteria” can be broken down as follows:
- Malar rash: butterfly-shaped rash across cheeks and nose
- Discoid (skin) rash: raised red patches
- Photosensitivity: skin rash as result of unusual reaction to sunlight
- Mouth or nose ulcers: usually painless
- Arthritis (nonerosive) in two or more joints, along with tenderness, swelling, or effusion. With nonerosive arthritis, the bones around joints don’t get destroyed.
- Cardio-pulmonary involvement: inflammation of the lining around the heart (pericarditis) and/or lungs (pleuritis)
- Neurologic disorder: seizures and/or psychosis
- Renal (kidney) disorder: excessive protein in the urine, or cellular casts in the urine
- Hematologic (blood) disorder: hemolytic anemia, low white blood cell count, or low platelet count
- Immunologic disorder: antibodies to double stranded DNA, antibodies to Sm, or antibodies to cardiolipin
- Antinuclear antibodies (ANA): a positive test in the absence of drugs known to induce it.
Learn more at the Lupus Research Alliance.