Table 1

Classification of axSpA with radiographic sacroiliitis using the mNY criteria for the classification of AS17 and the ASAS criteria for the classification of r-axSpA1

mNY criteria
for the classification of AS		ASAS criteria
for the classification of radiographic axSpA
1. Low back pain and stiffness for at least 3 months, which improves with exercise and is not relieved by rest
2. Limitation of lumbar spine motion in the sagittal and frontal planes
3. Decreased chest expansion compared with age-matched and sex-matched controls
4a. Unilateral sacroiliitis grade 3 or 4
4b. Bilateral sacroiliitis grade 2 to 4

  1. Back pain ≥3 months

  2. Age at onset <45 years

  3. Definite radiographic sacroiliitis according to mNY criteria

  4. ≥1 SpA feature

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  • Inflammatory back pain

  • Arthritis

  • Enthesitis

  • Uveitis

  • Dactylitis

  • Psoriasis

  • Crohn’s/colitis

  • Good response to NSAIDs

  • Family history for SpA

  • HLA-B27 positive

  • Elevated CRP (or ESR)

Definite AS if sacroiliitis as described in 4a or 4b and any of the clinical symptoms (1–3)Definite r-axSpA if fulfilment of 1 and 2, sacroiliitis as described in 3 and at least one of the clinical SpA features as described in 4

  • AS, ankylosing spondylitis; ASAS, Assessment of SpondyloArthritis international Society; axSpA, axial Spondyloarthritis; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; HLA-B27, human leucocyte antigen B27; mNY, modified New York; NSAID, non-steroidal anti-inflammatory drugs;r-axSpA, radiographic axial spondyloarthritis.