The incidence of the disease parallels the prevalence of the human leukocyte antigen B27, with which it is closely associated.
This is obtained through a blood sample and more than 90% of patients with ankylosing spondylitis are HLAB27 positive, while in the general population this prevalence is 7% (studies on this relationship continue to be carried out)
When disease is suspected, this blood test is performed to confirm it.
Having this antigen in the blood doesn't means that we will develop the disease. However, if it is positive, there is clinical data, affected relatives and radiological signs that suggest the disease is very likely to happen.