Table 1.

ASAS 2010 criteria for classification of axial spondyloarthritis [2,3,9].

Back pain ≥3 months and age at onset <45 years
Sacroiliitis on imaging* + ≥1 SpA feature**	or	HLA-B27 – positive + ≥2 other SpA features**

^*Active (acute) inflammation on MRI or definite radiographic sacroiliitis according to the modified New York criteria (1984) are highly suggestive of sacroiliitis associated with SpA.

^**SpA features: inflammatory back pain (at least 4 of the following symptoms must occur: 1. pain onset before the age of 40; 2. insidious onset; 3. improvement with exercise; 4. no improvement with rest; 5. pain at night, with improvement upon getting up), peripheral arthritis, enthesitis, uveitis, dactylitis, psoriasis, Crohn’s disease (CD) or ulcerative colitis (UC), good response to non-steroidal anti-inflammatory drugs, family history of SpA, HLA-B27, elevated CRP.