These criteria were developed by the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR). Twenty-three candidate items were considered, and reduced by clustering items and simplifying weights. The system was tested by comparing performance in scleroderma patients and control patients, and validated with a group of experts.
Skin thickening of the fingers extending proximal to the metacarpophalangeal joints is sufficient for a patient to be classified as having scleroderma. If this is not present, seven other additive items are considered, with varying weights for each (see below).
Patients with a total score of ≥ 9 are classified as having definite scleroderma.