Criteria

American College of Rheumatology (ACR) preliminary criteria for the classification of the acute arthritis of primary gout[55]

Diagnosis is satisfied by:

1. Characteristic monosodium urate crystals in joint fluid, or

2. Characteristic monosodium urate crystals from tophus, or

3. Fulfilment of ≥6 of the following criteria:

  • More than one attack of acute arthritis

  • Maximum inflammation developed within 1 day

  • Monoarthritis attack, redness observed over joints

  • First metatarsophalangeal joint painful or swollen

  • Unilateral first metatarsophalangeal joint attack

  • Unilateral tarsal joint attack

  • Tophus (confirmed or suspected)

  • Hyperuricaemia

  • Asymmetrical swelling within a joint on x-ray film

  • Subcortical cyst without erosions on x-ray film

  • Joint culture negative for organism during attack.

American College of Rheumatology/European League Against Rheumatism (ACR-EULAR) gout classification criteria[56][57]

In 2015 the ACR published new classification criteria; however, these criteria are intended for identifying people who may be eligible for entry into a clinical study and they are not intended to be used to diagnose gout.[56][57]

  • The sensitivity of the 2015 classification criteria is 92%, and the specificity is 89%.

  • The criteria include clinical, imaging, and laboratory-based features.

  • The maximum possible score in the final criteria is 23 and a threshold score of 8 classifies an individual as having gout.

  • A unique aspect of these classification criteria is that there are 2 categories that elicit negative scores. Specifically, if the synovial fluid is negative for monosodium urate, 2 points are subtracted from the total score. Similarly, if the serum urate level is <240 micromol/L (<4 mg/dL), 4 points are subtracted from the total score.

  • Associated Web-based calculators are available. ACR-EULAR gout classification criteria calculator Opens in new window

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