Overview

Autoantibodies are types of antibodies that target and react to your own body (called an autoimmune reaction). Several blood tests can be done to detect specific autoantibodies and help make the diagnosis of lupus. These blood tests alone cannot diagnose lupus, but combining the tests with a doctor's physical examination and other findings can help to clarify a diagnosis. These antibody blood tests include:

• Antinuclear antibody (ANA).
• Anti-dsDNA (antibodies to double-stranded DNA).
• Anti-RNP.
• Anti-Smith (Sm).
• Anti-SS-A (also called Ro).
• Anti-SS-B (also called La).
• Anti-Chromatin.
• Antiphospholipid antibodies.

These antibody tests are often positive in lupus and can provide support for a diagnosis if the clinical criteria are unclear or if the ANA test is negative but lupus is strongly suspected.

• ANA test: Antinuclear antibodies (ANAs) are autoantibodies to the nuclei and cellular content of healthy cells. 98% of all the people with lupus have a positive ANA test result. However, a positive ANA test result alone is not enough to diagnose lupus. A positive ANA test can also be seen in up to 1 in 5 healthy adults, and with several conditions that might cause autoantibodies, including infections, cancer, multiple sclerosis, or thyroid disease.
• Anti-dsDNA: High levels of anti-dsDNA are usually seen only in people who have lupus. This test can be repeated at different times to check how the disease is progressing.
• Anti-Smith (anti-Sm): People who do not have lupus usually do not have a positive anti-Sm test. But only approximately 3 out of 10 people with lupus have a positive anti-Sm test.
• Anti-SS-A (Ro) and anti-SS-B (La): Anti-SS-A (Ro) and anti-SS-B (La) antibodies are not specific to lupus. They are found more commonly in Sjögren's disease. But these tests are useful if you have lupus and are considering pregnancy. If you have these antibodies and become pregnant, you may need more careful monitoring of the fetus, since these antibodies are associated with a higher risk of the baby being born with neonatal lupus syndrome or a heart defect called congenital heart block.
• Antiphospholipid antibodies (aPL): These include lupus anticoagulant, anticardiolipin, and anti-beta 2 glycoprotein I. They are found in 3 to 4 out of 10 people with lupus. If you have a positive test for antiphospholipid antibodies, you may have a higher risk of thrombosis (blood clot), symptomatic coronary artery disease, stroke, and issues during pregnancy.