The guideline recommends referral using the criteria for which there was best-quality evidence. This referral tool (Box 3) not only uses some of the features of IBP but also other diagnostic features such as dactylitis, which are diagnostic of SpA, and associated features such as inflammatory bowel disease and psoriasis. Referral is recommended if a patient has low back pain that started before the age of 45 years and has lasted >3 months, and four or more of the additional criteria in Box 3 are also present. If three of the additional criteria are present, an HLA-B27 test should be performed and the patient referred if the test is positive. If the patient does not meet the criteria for referral in Box 3, but clinical suspicion of axial SpA remains, the patient should be advised to seek repeat assessments if any of the signs, symptoms, or risk factors listed in Box 2 develop. This may be especially appropriate if the patient has current or past inflammatory bowel disease (Crohn’s disease or ulcerative colitis), psoriasis, or uveitis.
Box 3. Axial spondyloarthritis referral criteria for patients who have low back pain that started before the age of 45 years and that has lasted >3 months
Low back pain that started before the age of 35 years (more likely to be due to spondyloarthritis (SpA) compared with low back pain that started between 35 and 44 years).
Waking during the second half of the night because of symptoms.
Buttock pain.
Improvement with movement.
Improvement within 48 hours of taking non-steroidal anti-inflammatory drugs (NSAIDs)
A first-degree relative with SpA.
Current or past arthritis.
Current or past enthesitis.
Current or past psoriasis.
The clinician should refer if the patient fulfils four of the criteria. If three criteria are fulfilled, an HLA-B27 test should be performed and the patient referred if the test is positive.
The referral pathway may seem complicated but it was designed to improve the specificity of referrals into the rheumatology services and prevent referrals for mechanical back pain, which are better dealt with in the musculoskeletal service.
