A 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.
A positive result means HLA-B27 was found in your blood. You may have a higher-than-average risk of certain autoimmune diseases, such as ankylosing spondylitis and reactive arthritis. If you are white, you are more likely to test positive for the HLA-B27 antigens.
The first human leukocyte antigen (HLA) haplotype association with human inflammatory disease was discovered in 1972, correlating HLA-B27 with ankylosing spondylitis. This remains one of the strongest known associations of this disease with HLA-B27. Since then, more than 100 disease associations have been made, including many exclusively ocular diseases and also systemic diseases with specific ocular manifestations.  These latter conditions include reactive arthritis (previously referred to as Reiter syndrome), inflammatory bowel disease, and psoriatic arthritis.