Refer patients with suspected axial spondyloarthritis to secondary care if they have low back pain starting before the age of 45 years and lasting longer than 3 months, with four or more additional diagnostic criteria present, or if exactly three criteria are present and the HLA‑B27 test is positive NICE NG65.
Additional criteria include: low back pain starting before age 35, waking during the night due to symptoms, buttock pain, improvement with movement, improvement within 48 hours of NSAID use, a first-degree relative with spondyloarthritis, current or past arthritis, enthesitis, or psoriasis NICE NG65.
If the criteria are not fully met but clinical suspicion remains high, referral should be considered if new signs or symptoms develop, especially in the context of associated conditions like inflammatory bowel disease, psoriasis, or uveitis NICE NG65.
For suspected psoriatic or peripheral spondyloarthritis, urgent referral is recommended if new-onset inflammatory arthritis is suspected, or if there are signs such as dactylitis or persistent enthesitis, especially with additional features like uveitis or psoriasis NICE NG65.
In cases where plain X-ray does not show sacroiliitis meeting the modified New York criteria, an MRI should be arranged, and referral to a rheumatologist should be made for further assessment NICE NG65.