Synonyms:

• Ankylosing Spondylitis
• B27 Disease Association
• Disease Association Testing
• HLA Antigen B27

The HLA-B27 Disease Association blood test is used to evaluate spondyloarthritis and other disorders associated with HLA-B27.

HLA-B27 is strongly associated with ankylosing spondylitis (Marie-Strumpell disease). HLA-B27 shares homology with a Klebsiella protein and may imply a bacterial pathogenesis to ankylosing spondylitis. A patient with consistent clinical and radiographic findings who is B27-positive has a greater chance of having or developing ankylosing spondylitis than a negative patient. The antigen is not causative, however, and 10% of normal subjects are B27-positive. This test should not be considered a screening procedure for ankylosing spondylitis. The antigen is less strongly associated with Reiter syndrome and other arthritides than with ankylosing spondylitis. It has been linked with congenital deficiency of C₄ and C₂, and with adrenal hyperplasia.