HLA typing; Tissue typing DefinitionA histocompatibility antigen blood test looks at proteins called human leukocyte antigens (HLAs). These are found on the surface of almost all cells in the human body. HLAs are found in large amounts on the surface of white blood cells. They help the immune system tell the difference between body tissue and substances that are not from your own body. How the Test is PerformedBlood is drawn from a vein. You may feel slight pain or a sting when the needle is inserted. Afterward, there may be some throbbing. How to Prepare for the TestYou do not need to prepare for this test. How the Test will Feel
Why the Test is PerformedThe results from this test can be used to identify good matches for tissue grafts and organ transplants. These may include kidney transplant or bone marrow transplant. It may also be used to:
Normal ResultsYou have a small set of HLAs that are passed down from your parents. Children, on average, will have half of their HLAs match half of their mother's and half of their HLAs match half of their father's. It is unlikely that two unrelated people will have the same HLA makeup. However, identical twins may match each other. Some HLA types are more common in certain autoimmune diseases. For example, HLA-B27 antigen is found in many people (but not all) with ankylosing spondylitis and Reiter syndrome. RisksThere is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others. Other risks associated with having blood drawn are slight, but may include:
ReferencesBray R, Sullivan C, 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. Monos DS, Rajalingam R. The major histocompatibility complex. 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 5. Wang E, Adams S, Stroncek DF, Marincola FM. Human leukocyte antigen and human neutrophil antigen systems. In: Hoffman R, Benz EJ, Silberstein LE et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 114. | |
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Review Date: 1/24/2023 Reviewed By: Anna C. Edens Hurst, MD, MS, Associate Professor in Medical Genetics, The University of Alabama at Birmingham, Birmingham, AL. 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. 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
