HLA-B27 is an antigen and the test for this is also known by names, such as histocompatibility leukocyte A antigen; human leukocyte A antigen and Human Lymphocyte Antigen B27.
If you are HLA-B27 positive, then it means that you are at increased risk than others for some autoimmune conditions like reactive arthritis and ankylosing spondylitis.(1, 2) White people are more likely to have a HLA-B27 positive test.(4)
More About The HLA-B27 Test and Why Is It Done
The HLA-B27 test is done if your doctor suspects you are suffering from autoimmune disease, such as Ankylosing spondylitis. The HLA-B27 test is done to look for the presence of HLA-B27 that is present on the surface of white blood cells. The HLA-B27 are proteins and if you test positive for it, then it means that you can have an autoimmune disease or the chance of you getting an autoimmune disease is high. The HLA antigens are determined by a person’s genes and are unique for every individual.
Some of the common autoimmune conditions that are linked with HLA-B27 are: Juvenile arthritis, Ankylosing spondylitis, and Reactive arthritis.
The HLA-B27 test is also done if a person is having a tissue or organ transplant. In order for the transplant to be successful, the donor’s HLA antigens should match with the recipient’s.
Are There Any Other Tests That Need To Be Done With The HLA-B27 Test?
After a positive HLA-B27 antigen test, other tests need to be done to confirm the diagnosis of an autoimmune disease and these tests include: C-reactive protein,
Erythrocyte Sedimentation Rate (ESR), urine test, and joint MRI/X-rays.
The Meaning of the HLA-B27 Test Results
The results of the HLA-B27 test can differ depending on the patient’s gender, age, medical history and the methodology used for the test.
If you have a negative result then it means that HLA-B27 is not present in your blood. If you have a positive result, then it means that HLA-B27 is present in your blood, which increases you chances of having certain autoimmune diseases. Caucasians are more likely to test positive for the HLA-B27 antigens.(4)
The Risks and the Method of the HLA-B27 Test
The HLA-B27 test is done by drawing a blood sample with the help of a needle from a vein in your hand or arm. A blood test done with a needle has few risks that include: infection, bleeding, lightheadedness and bruising. There is a mild pain or sting felt when the needle pricks your vein and some soreness afterwards, which goes away soon.
Factors That Affect the HLA-B27 Test Results and Preparation of This Test
There aren’t any particular factors that affect the results of HLA-B27 test.
Before undergoing this test, you need to inform your healthcare provider about all the medicines, supplements and herbs that you are taking including over the counter medicines and illegal drugs if any.