About the ACR/EULAR gout classification criteria
This calculator implements the 2015 American College of Rheumatology / European League Against Rheumatism (ACR/EULAR) gout classification criteria, a validated points-based tool for classifying gout in a patient who has had at least one episode of peripheral joint or bursa swelling, pain, or tenderness. The criteria combine clinical features, serum urate, and imaging into a single score; a total of 8 or more points meets the classification threshold.
How the score is built
- Sufficient criterion: if monosodium urate (MSU) crystals have been identified in synovial fluid from a symptomatic joint or bursa, or in a tophus, the case is classified as gout directly, without needing the point score.
- Clinical points: joint/bursa pattern (0-2), number of episode characteristics such as redness, inability to bear touch, and difficulty walking (0-3), time course of typical episodes (0-2), and clinical evidence of tophus (0 or 4).
- Laboratory points: serum urate scored from -4 to +4 depending on the concentration band, and synovial fluid analysis that is negative for MSU crystals (-2, or 0 if not tested).
- Imaging points: ultrasound double-contour sign or dual-energy CT (DECT) evidence of urate deposition (0 or 4), and conventional radiography showing gout-related erosion in the hands or feet (0 or 4).
Interpreting the result
Add the clinical, laboratory, and imaging points to get the total score. A total of 8 or more points meets the ACR/EULAR classification threshold for gout. This threshold was derived and validated against synovial fluid crystal identification as the reference standard, so it functions best as a classification and research tool rather than a bedside diagnosis on its own.
When to consult a professional
This calculator performs the standard ACR/EULAR point arithmetic; it does not replace joint aspiration, crystal identification, or a clinician's evaluation. Any diagnosis or treatment decision for suspected gout should be made with a licensed healthcare provider.