Human leukocyte antigen B27; Ankylosing spondylitis-HLA; Psoriatic arthritis-HLA; Reactive arthritis-HLA DefinitionHLA-B27 is a blood test to look for a protein that is found on the surface of white blood cells. The protein is called human leukocyte antigen B27 (HLA-B27). Human leukocyte antigens (HLAs) are proteins that help the body's immune system tell the difference between its own cells and foreign, harmful substances. They are made from instructions by inherited genes. How the Test is PerformedA blood sample is needed. Most of the time, blood is drawn from a vein located on the inside of the elbow or the back of the hand. How to Prepare for the TestNo special steps are needed to prepare for the test. How the Test will FeelWhen the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing. Why the Test is PerformedYour health care provider may order this test to help determine the cause of joint pain, stiffness, or swelling. The test may be done along with other tests, including:
HLA testing is also used to match donated tissue with a person's tissue who is getting an organ transplant. For example, it may be done when a person needs a kidney transplant or bone marrow transplant. Normal ResultsA normal (negative) result means HLA-B27 is absent. What Abnormal Results MeanA positive test means HLA-B27 is present. It suggests a greater-than-average risk for developing or having certain autoimmune disorders. An autoimmune disorder is a condition that occurs when the immune system mistakenly attacks and destroys healthy body tissue. A positive result can help your provider make a diagnosis of a form of arthritis called spondyloarthritis. This kind of arthritis includes the following disorders:
If you have symptoms or signs of spondyloarthritis, a positive HLA-B27 test may help confirm the diagnosis. However, HLA-B27 is found in some normal people and does not always mean you have a disease. RisksRisks from having blood drawn are slight, but may include:
ReferencesBray R, Sullivan HC, Krummey S, Gebel HM. Human leukocyte antigen: the major histocompatibility complex of humans. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 50. Lienesch DW. Spondyloarthritis. In: Wing EJ, Schiffman FJ, eds. Cecil Essentials of Medicine. 10th ed. Philadelphia, PA: Elsevier; 2022:chap 80. McPherson RA, Massey HD. Overview of the immune system and immunologic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 44. Reveille JD, Ridley LK. Spondyloarthritis. In: Rich RR, Fleisher TA, Schroeder HW, Weyand CM, Corry DB, Puck JM, eds. Clinical Immunology: Principles and Practice. 6th ed. Philadelphia, PA: Elsevier; 2023:chap 58. | ||
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Review Date: 4/30/2023 Reviewed By: Neil J. Gonter, MD, Assistant Professor of Medicine, Columbia University, New York, NY, and private practice specializing in Rheumatology at Rheumatology Associates of North Jersey, Teaneck, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. View References 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. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. | ||
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Blood test
