Anti-smooth muscle antibody is a blood test that detects the presence of antibodies against smooth muscle. The antibody is useful in making a diagnosis of autoimmune hepatitis.
A blood sample is needed. This may be taken through a vein. The procedure is called a venipuncture.
No special steps are needed to prepare for this test.
When the needle is inserted to draw blood, some people feel moderate pain. Others may feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Anti-smooth muscle antibodies are not often seen in diseases other than autoimmune hepatitis. Therefore, it is helpful to make the diagnosis. Autoimmune hepatitis is treated with immunosuppressive medicines. People with autoimmune hepatitis often have other autoantibodies. These include:
The diagnosis and management of autoimmune hepatitis may require a liver biopsy.
Normally, there are no antibodies present.
Note: Normal value ranges may vary slightly among different laboratories. Talk to your health care provider about the meaning of your specific test results.
A positive test may be due to:
Risks associated with having blood drawn are slight, but may include:
Czaja AJ. Autoimmune hepatitis. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology/Diagnosis/Management. 10th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 90.
Ferri FF. Laboratory values and interpretation of results. In: Ferri FF, ed. Ferri's Best Test: A Practical Guide to Clinical Laboratory Medicine and Diagnostic Imaging. 4th ed. Philadelphia, PA: Elsevier; 2019:129-227.
Manns MP, Lohse AW, Vergani D. Autoimmune hepatitis--Update 2015. J Hepatol. 2015;62(1 Suppl):S100-S111. PMID: 25920079 www.ncbi.nlm.nih.gov/pubmed/25920079.BACK TO TOP
Review Date: 1/10/2019
Reviewed By: Gordon A. Starkebaum, MD, MACR, ABIM Board Certified in Rheumatology, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2019 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.