Diagnosis of Ankylosing Spondylitis involves medical tests, analysis of the patient’s medical and family history, blood tests and imaging tests like X-ray. The doctor may conduct a general physical examination to check for tenderness along the pelvic bones, back, chest and sacroiliac joints.

Sometimes doctors also check chest expansion to identify any restriction in chest expansion and subsequent breathing problems. Doctors also check spinal mobility in different directions. They will also analyze the patient’s medical history and family history. A history of uveitis, gastrointestinal infections or a family history of arthritis or spondylitis will affect the diagnosis. Blood tests will also be recommended. The presence of C-reactive protein (CRP) in blood indicates inflammation. Similarly, an increased ESR (erythrocyte sedimentation rate) also indicated inflammation.

Blood may also be analyzed for the presence of the HLA-B27 gene marker. Its presence is not indicative of Ankylosing Spondylitis. It just indicates that there is a tendency to develop this condition or other forms of arthritis. X-rays of people with advanced Ankylosing Spondylitis may also show erosion of sacroiliac joints. However, early signs of this disease are not usually visible on X-rays. Sometimes, doctors recommend MRI scans or CT scan to detect inflammation and changes in joints.