What are the diagnostic criteria for ankylosing spondylitis (AS)?

Updated: Feb 02, 2021
  • Author: Lawrence H Brent, MD; Chief Editor: Herbert S Diamond, MD  more...
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The diagnosis of ankylosing spondylitis (AS) is generally made by combining clinical criteria of inflammatory back pain and enthesitis or arthritis with radiologic findings. [6, 7, 8] Two sets of sensitive and specific criteria are available for diagnosis of spondyloarthropathy in general: (1) the European Spondyloarthropathy Study Group (ESSG) criteria and (2) the Amor criteria (see Table 5 below). Two other sets are used widely for diagnosis of AS: the New York criteria and the Rome criteria (see Table 6 below).

Table 5. ESSG and Amor Criteria for Diagnosis of Spondyloarthropathy (Open Table in a new window)

ESSG Criteria

Amor Criteria*

Inflammatory spinal pain or synovitis and one of the following:

Inflammatory back pain

1 point

Alternating buttock pain

Unilateral buttock pain

1 point


Alternating buttock pain

2 points



2 points


Peripheral arthritis

2 points

Positive family history of spondyloarthropathy

Dactylitis (sausage digit)

2 points


Acute anterior uveitis

2 points


HLA-B27 positive or family history of spondyloarthropathy

2 points


Good response to NSAIDs

2 points

*Diagnosis of spondyloarthropathy with 6 or more points.

European Spondyloarthropathy Study Group (ESSG); IBD = inflammatory bowel disease; NSAID = nonsteroidal anti-inflammatory drug.

Table 6. New York and Rome Criteria for Diagnosis of Ankylosing Spondylitis (Open Table in a new window)

New York Criteria

Rome Criteria

  • Low back pain with inflammatory characteristics

  • Limitation of lumbar spine motion in sagittal and frontal planes

  • Decreased chest expansion

  • Bilateral sacroiliitis grade 2 or higher

  • Unilateral sacroiliitis grade 3 or higher

  • Low back pain and stiffness for >3 months that is not relieved by rest

  • Pain and stiffness in the thoracic region

  • Limited motion in the lumbar spine

  • Limited chest expansion

  • History of uveitis

Definite ankylosing spondylitis when the fourth or fifth criterion mentioned presents with any clinical criteria

Diagnosis of ankylosing spondylitis when any clinical criteria present with bilateral sacroiliitis grade 2 or higher

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