Consider the diagnosis of ankylosing spondylitis at any age in patients with chronic inflammatory back pain and decreased spinal mobility.
Ask about symptoms of spondyloarthropathy in patients with predisposing comorbid conditions such as inflammatory bowel disease and other forms of inflammatory arthritis.
Evaluate patients with suspected ankylosing spondylitis for limited mobility of the spine, limited chest expansion, or both.
Perform a plain radiograph of the pelvis to look for sacroiliitis in patients with suspected ankylosing spondylitis and consider MRI in unclear cases.
Consider testing for HLA-B27 and markers of inflammation in patients with intermediate probability of ankylosing spondylitis.
Use validated criteria such as the Modified New York Criteria or the ASAS Criteria to make the diagnosis.