Diagnosis

Diagnosing Ankylosing Spondylitis

In patients with persistent lower back pain, X-ray imaging is the primary diagnostic tool used to confirm ankylosing spondylitis (AS), as it can reveal inflammation and fusion of the spinal vertebrae.¹

X-rays are essential in distinguishing AS from its non-radiographic counterpart, axial spondyloarthritis, where such changes are only visible on MRI.

In addition to X-rays, your doctor may conduct blood tests to identify markers associated with the causes of AS , such as inflammatory cytokines released by immune cells and the presence of the HLA-B27 gene.¹

Despite the availability of these diagnostic techniques, AS remains widely under-diagnosed.² Several factors contribute to this:

AS often has a gradual onset, so symptoms may go unnoticed until the disease has progressed¹
There is no single definitive test to confirm AS¹
AS is frequently misdiagnosed due to symptom overlap—particularly back pain—with other more common conditions³

Giving symptom details, such as their timing and exacerbating factors, could aid in your diagnosis

References

Ankylosing Spondylitis Overview– NHS. Available at: https://www.nhs.uk/conditions/ankylosing-spondylitis/. Last accessed April 2025.
Axial spondyloarthritis (including ankylosing spondylitis): How should I assess a person with suspected axial spondyloarthritis?– NICE CKS. Available at: https://cks.nice.org.uk/topics/axial-spondyloarthritis-including-ankylosing-spondylitis/diagnosis/diagnosis/. Last accessed April 2025.
Ankylosing Spondylitis Overview– Creaky Joints. Available at: https://creakyjoints.org/about-arthritis/axial-spondyloarthritis/axspa-overview/ankylosing-spondylitis-facts/. Last accessed April 2025.