Antibody Tests for Lupus

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Antibody Tests for Lupus

Topic Overview

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 titres of anti-dsDNA are usually seen only in people with lupus.
  • 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

By Healthwise Staff
Primary Medical Reviewer Anne C. Poinier, MD - Internal Medicine
Primary Medical Reviewer Andrew Swan, MD, CCFP, FCFP - Family Medicine
Specialist Medical Reviewer Stanford M. Shoor, MD - Rheumatology
Last Revised July 8, 2010

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