This test evaluates spondylitis and other disorders associated with HLA-B27. It helps screen for the presence of a protein that is found on the surface of white blood cells, where HLA B27 is very strongly associated with ankylosing spondylitis (Marie-strumpell disease). A patient with consistent radiographic findings who is B27 positive has a slight chance of already having or developing ankylosing spondylitis. However, the test should not be considered as a screening procedure for ankylosing spondylitis. It has been linked with congenital deficiency of C4 and C2 and with adrenal hyperplasia.
LabEspy recommends Direct Labs for this test.