2015 ACR/EULAR gout classification criteria

Q: How many points classify gout?

8 or more (maximum 23), unless MSU crystals are found, which is sufficient on its own.

Q: What serum urate unit should I use?

The criteria give both: < 0.24 mmol/L (< 4 mg/dL) −4, 0.36–< 0.48 mmol/L +2, 0.48–< 0.60 +3, ≥ 0.60 mmol/L +4.

Q: What is the double-contour sign?

A hyperechoic irregular line over the surface of hyaline cartilage on ultrasound, independent of the insonation angle, reflecting urate deposition.

Classifies gout from clinical, laboratory and imaging findings (≥ 8 points)

ACR/EULAR 2015

Sources last checked: 2026-10-13

2015 ACR/EULAR gout classification criteria

Classifies gout from clinical, laboratory and imaging findings (≥ 8 points)

≥ 1 episode of swelling, pain or tenderness in a peripheral joint or bursa

Synovial fluid / tophus aspirate (polarising microscopy by a trained observer)

Joints/bursae involved in symptomatic episode(s) ever

Episode characteristics ever: erythema · can't bear touch/pressure · great difficulty walking or using the joint

Typical episodes (≥ 2 of: max pain < 24 h · resolution ≤ 14 days · complete resolution between episodes)

Clinical evidence of tophus+4

Serum urate (uricase method; highest value, ideally off urate-lowering therapy and > 4 weeks after an episode)

Imaging of urate deposition: ultrasound double-contour sign or DECT urate+4Gout-related erosion on hand/foot radiograph+4

Fill in every field to see the result.

Classification criteria (sensitivity 92 %, specificity 89 % in validation), not a diagnostic test — MSU crystal identification in joint or tophus aspirate remains the diagnostic reference standard. Missing imaging or synovial fluid scores 0, which lowers sensitivity.

Source: Neogi T, Jansen TL, Dalbeth N, et al. 2015 Gout classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Ann Rheum Dis 2015;74(10):1789-1798.Open

Interpretation

Criteria not applicable	Entry criterion not met.
Not classified as gout (< 8 points)	Not classified on the current findings. Under the criteria, MSU crystals in a symptomatic joint or bursa are sufficient on their own.
Classified as gout	Sufficient criterion (MSU crystals) met, or score ≥ 8.

What is the 2015 ACR/EULAR gout classification criteria?

The 2015 ACR/EULAR gout classification criteria work in three steps: an entry criterion (at least one episode of peripheral joint or bursa symptoms), a sufficient criterion (MSU crystals), and a weighted score across clinical, laboratory and imaging domains. A score of 8 or more out of 23 classifies gout. Developed by Neogi, Jansen, Dalbeth and colleagues, they reached 92 % sensitivity and 89 % specificity in validation.

When to use it

To classify gout for studies and registries
To structure the assessment when crystal identification is not available
To document which features support the diagnosis

When not to use it

Instead of joint aspiration when it is feasible — finding MSU crystals is decisive
In asymptomatic hyperuricaemia (entry criterion not met)

How it is calculated

Step 1 — entry: ≥ 1 episode of peripheral joint/bursa swelling, pain or tenderness. Step 2 — sufficient: MSU crystals in a symptomatic joint/bursa or tophus → gout. Step 3 — score: pattern (ankle/midfoot 1, first MTP 2) · characteristics (1/2/3) · time course (one typical episode 1, recurrent 2) · tophus 4 · serum urate (< 0.24 mmol/L −4; 0.24–< 0.36: 0; 0.36–< 0.48: 2; 0.48–< 0.60: 3; ≥ 0.60: 4) · synovial fluid MSU-negative −2 · imaging urate deposition 4 · radiographic erosion 4. Maximum 23; ≥ 8 = gout.

Clinical pearls and limitations

Classification criteria (sensitivity 92 %, specificity 89 % in validation), not a diagnostic test — MSU crystal identification in joint or tophus aspirate remains the diagnostic reference standard. Missing imaging or synovial fluid scores 0, which lowers sensitivity.
Score the highest serum urate on record, ideally off urate-lowering therapy and more than 4 weeks after a flare.
Two items can subtract points: urate < 0.24 mmol/L (−4) and MSU-negative synovial fluid (−2).
Imaging items (ultrasound double-contour sign or DECT urate; radiographic erosion) are worth 4 points each.
A clinical-only version without fluid or imaging was less sensitive (85 %) and specific (78 %).

Frequently asked questions

How many points classify gout?

8 or more (maximum 23), unless MSU crystals are found, which is sufficient on its own.

What serum urate unit should I use?

The criteria give both: < 0.24 mmol/L (< 4 mg/dL) −4, 0.36–< 0.48 mmol/L +2, 0.48–< 0.60 +3, ≥ 0.60 mmol/L +4.

What is the double-contour sign?

A hyperechoic irregular line over the surface of hyaline cartilage on ultrasound, independent of the insonation angle, reflecting urate deposition.

Evidence and guidelines

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