Unlike other chronic illnesses, trying to reach a diagnosis of lupus isn't always easy. To help the doctors diagnose lupus, a list of 11 common criteria, or measures, was developed by the American College of Rheumatology. If you have at least four of the criteria on the list, either at the present time or at some time in the past, there is a strong chance that you have lupus. 
- Malar rash - a rash over the cheeks and nose, often in the shape of a butterfly
- Discoid rash - a rash that appears as red, raised, disk-shaped patches
- Photosensitivity - a reaction to sun or light that causes a skin rash to appear or get worse
- Oral ulcers - sores appearing in the mouth
- Arthritis - joint pain and swelling of two or more joints in which the bones around the joints do not become destroyed
- Serositis - Inflammation of the lining around the lungs (pleuritis) or inflammation of the lining around the heart that causes chest pain which is worse with deep breathing (pericarditis)
- Kidney Disorder - persistent protein or cellular casts in the urine
- Neurological disorder - seizures or psychosis
- Blood disorder - anemia (low red blood cell count), leukopenia (low white blood cell count) lymphopenia (low level of specific white blood cells), thrombocytopenia (low platelet count)
- Immunologic disorder - abnormal anti-double-stranded DNA or anti-Sm, positive antiphospholipid antibodies
- Abnormal antinuclear antibody (ANA)
People with lupus may also experience symptoms that do not appear among the ACR criteria, such as a fever of more than100 degrees, extreme fatigue, hair loss, and fingers turning white and/or blue when cold, to name a few.
For more information check out the new interactive "Could you have lupus?" checklist at LUPUS.ORG.