This is a blood test to detect the presence of HLA-B27 in white
blood cells.
The test is conducted to look for specific protein found on the
surface of white blood cells. The protein is called human leukocyte
antigen B27 (HLA-B27) that help the body's immune system tell the
difference between its own cells and foreign, harmful
substances.
The test is referred when you have symptoms of chronic
inflammation, pain, and stiffness in certain areas of your body,
such as your back, neck, and chest, or eyes, especially if you are
male. A positive test means HLA-B27 is present. It suggests a
greater-than-average risk for developing Ankylosing spondylitis,
Reiter syndrome or Sacroiliitis (inflammation of the sacroiliac
joint).
If HLA-B27 is not present, then the association is not
there.