Limited validity of the American College of Rheumatology criteria for classifying patients with gout in primary care

Abstract

In order to classify gout without identifi cation of monosodium urate (MSU) crystals, the American College of Rheumatology (ACR) formulated criteria in 1977. Of the 11 criteria, ≥6 have to be present to classify patients as having gout. The criteria were not developed with reference to MSU crystals, nor were they tested properly afterwards against this gold standard. However, as they are widely used and cited, testing their validity is critical to our ability to understand and treat gout.