Making the Diagnosis
An antinuclear antibody (ANA) test is the most important test for lupus, as almost all people with lupus will have elevated blood levels of antinuclear antibodies. However, a diagnosis will not be based on ANA results alone, because many people have positive ANA tests without lupus, and it can also occur in other autoimmune diseases. A person with a positive ANA test but who does not have clinical signs or other lab abnormalities has about a 5% chance of developing full-blown lupus over a lifetime.
Your medical history and a physical examination done by your doctor will play an important role in making the diagnosis. Other laboratory studies such as tests of kidney function, as well as joint X-rays and MRI (magnetic resonance imaging) scans, will help determine the extent of the disease.
People may need heart tests and an electroencephalogram (test to measure electrical activity of the brain) to detect neurolupus (lupus that affects the brain).