A 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.
Blood is drawn from a vein. You may feel slight pain or a sting when the needle is inserted. Afterward, there may be some throbbing.
You do not need to prepare for this test.
The 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:
You 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.
Slight risks from having blood drawn may include:
Reviewed By: Frank A. Greco, MD, PhD, Director, Biophysical Laboratory, Edith Nourse Rogers Memorial Hospital, Bedford, MA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.