Antibody tests for lupus
Antibody tests are a set of blood tests that check for specific antibodies to help clarify the diagnosis of lupus. They include:
- Anti-SS-A (also called Ro).
- Anti-SS-B (also called La).
- Anti-dsDNA (antibodies to DNA).
- Anti-RNP.
- Anti-Smith (Sm).
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.
- Anti-SS-A (Ro) and anti-SS-B (La) antibodies are not specific for lupus and are found commonly in Sjögren's syndrome. However, these tests are useful in helping women with lupus who are considering pregnancy. If a woman who has these antibodies becomes pregnant, she 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.1
- High titers of anti-dsDNA are usually seen only in people with lupus.
- A positive anti-dsDNA suggests a higher risk of developing lupus-related kidney disease.
- A positive anti-Sm test is a specific marker for lupus and may be associated with more severe cases.
Anti-dsDNA tests can be repeated at intervals to monitor how the disease is progressing.
| Author: | Shannon Erstad, MBA/MPH | Last Updated: May 13, 2008 |
| Medical Review: | Adam Husney, MD - Family Medicine Anne C. Poinier, MD - Internal Medicine Stanford M. Shoor, MD - Rheumatology | |
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