Antibody tests for lupus

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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.

References

Citations

1. Crow MK (2008). Systemic lupus erythematosus. In L Goldman, D Ausiello, eds., Cecil Textbook of Medicine, 23rd ed., pp. 2022–2032. Philadelphia: Saunders Elsevier.

Credits

Last updated:	May 13, 2008
Author:	Shannon Erstad, MBA/MPH
Reviewed By:	Anne C. Poinier, MD - Internal Medicine, Stanford M. Shoor, MD - Rheumatology
Editors:	Kathleen M. Ariss, MS, Pat Truman, MATC