Human Leukocyte antigen (HLA) is a protein (antigen) present in the WBCs (white blood cells). These surface antigens help in distinguishing foreign cells and body’s own cells and thus differentiate self from foreign cells (nonself). Though HLAs help protect the blood cells from foreign substances, there are some like HLA-B27, which are responsible for the immune system’s abnormal function. These antigens are responsible for abnormal immune reaction and lead to autoimmune disorders. The HLA-B27 test helps in determining the presence of HLA-B27 antigen in white blood cells in the patient’s body.
Why the test is ordered?
The HLA-B27 test may be ordered along with other tests, such as ESR, CRP and RF to help evaluate the conditions causing inflammation, pain, stiffness and arthritis like symptoms in a patient’s body. The test may also be ordered for a person undergoing organ transplant – kidney, liver, heart, bone marrow, etc.. to ensure a match between the donor and recipient. It is also useful in testing an individual with recurrent uveitis if the cause is unknown.
When is the test ordered?
The test may be ordered if a doctor suspects an autoimmune disorder owing to HLA-B27 in a person suffering from acute or chronic pain and inflammation in the neck, chest, spine, joint and eyes. The test may also be ordered for an individual with recurrent uveitis.
How is the sample collected?
A blood sample is collected from a vein in the arm.
How to prepare for the test?
No special preparations are required for this test.