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-dsDNA (antibodies to DNA).
- Antinuclear antibody (ANA)
- Anti-RNP.
- Anti-Smith (Sm).
- Anti-SS-A (also called Ro).
- Anti-SS-B (also called La).
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. But 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.
- High titers of anti-dsDNA are usually seen only in people who have lupus.
- A positive anti-Sm test is a specific marker for lupus.
Anti-dsDNA tests can be repeated at intervals to monitor how the disease is progressing.
References
Other Works Consulted
- Crow MK (2016). Systemic lupus erythematosus. In L Goldman, A Shafer, eds., Goldman-Cecil Medicine, 24th ed., vol. 2, pp. 1769–1777. Philadelphia: Saunders.
- Hahn BH (2015). Systemic lupus erythematosus. In DL Kasper et al., eds., Harrison’s Principles of Internal Medicine, 19th ed., vol. 2, pp. 2124–2134. New York: McGraw-Hill Education.
Credits
Current as ofApril 1, 2019
Author: Healthwise Staff
Medical Review: Anne C. Poinier MD – Internal Medicine
Martin J. Gabica MD – Family Medicine
E. Gregory Thompson MD – Internal Medicine
Kathleen Romito MD – Family Medicine
Nancy Ann Shadick MD, MPH – Internal Medicine, Rheumatology
