HLA-B27 positivity should be highly alert for ankylosing spondylitis. However, the diagnosis of the disease requires further joint judgment by the doctor through medical history, joint ultrasound X-rays, CT and MRI. HLA-B27 is short for human leukocyte antigen B27, a genetic marker. The vast majority of ankylosing spondylitis patients are positive for HLA-B27. Those who are negative for HLA-B27 may also have ankylosing spondylitis, but the chances are relatively low, so HLA-B27 should not be used as a means of confirming the diagnosis, and further diagnosis needs to be made by the doctor through medical history and imaging tests. The HLA-B27 gene is closely related to ankylosing spondylitis as well as uveitis, so if you are found to be HLA-B27 positive, you should go to the hospital in time to find out the cause of the disease and get prompt treatment.