Calc Function

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    Chief Complaint


    Organ System


    Patent Pending

    ASAS Criteria for Axial Spondyloarthritis (SpA)

    Diagnoses axial spondyloarthritis according to Assessment of Spondyloarthritis International Society (ASAS) criteria.
    When to Use

    Patients with lower back pain in whom spondyloarthritis is in the differential diagnosis.

    Entry Criterion

    Diagnostic Result:

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    Next Steps
    Creator Insights


    Strong recommendations for patients with axial SpA from the American College of Rheumatology (ACR) include:

    • Use of NSAIDs.
    • Use of TNF inhibitors if activity persists despite NSAIDs.
    • Avoid using systemic glucocorticoids.
    • Physical therapy.
    • Hip arthroplasty for patients with advanced hip arthritis.


    Entry criterion:

    Back pain ≥3 months and age at onset <45 years

    Required criteria:

    Sacroiliitis on imaging* plus ≥1 SpA feature, or

    HLA-B27 plus ≥2 additional SpA features

    SpA features:

    • Inflammatory back pain
    • Arthritis
    • Enthesitis (heel)
    • Uveitis
    • Dactylitis
    • Psoriasis
    • Crohn’s disease or ulcerative colitis
    • Good response to NSAIDs
    • Family history of SpA
    • HLA-B27
    • Elevated CRP

    *Active (acute) inflammation on MRI highly suggestive of SpA-associated sacroiliitis, or definite radiographic sacroiliitis according to modified New York criteria (bilateral grade 2-4 sacroiliitis or unilateral grade 3-4 sacroiliitis, Van Der Linden 1984).


    Dr. Martin Rudwaleit

    About the Creator

    Martin Rudwaleit, MD, is a rheumatologist at University Hospital Charité, Campus Benjamin Franklin, in Berlin, Germany. He is the principal coordinator of the German Spondyloarthritis Inception Cohort, a prospective longitudinal study on early spondyloarthritis. Dr. Rudwaleit's research interests include clinical aspects of ankylosing spondylitis and other spondyloarthritides.

    To view Dr. Martin Rudwaleit's publications, visit PubMed