🦶 Gout Classification Criteria Scorer

The 2015 ACR/EULAR criteria classify gout by points: a first-MTP attack (+2) with erythema and inability to bear touch (+2), two self-resolving episodes (+2), and serum urate 9 (+3) totals 9, classifying gout at the 8-point threshold. Crystal proof (MSU seen) confirms it without scoring. Work through the steps above.

How to Use This Scorer

Neogi et al. published these classification criteria in 2015, validated at 92% sensitive and 89% specific against crystal-proven gout. They classify established disease for studies and guide clinical diagnosis.

The Domains and Points

The weights encode clinical wisdom: tophus and imaging each score 4 because they are nearly pathognomonic, while a low serum urate subtracts 4 because gout with urate under 4 mg/dL is uncommon enough to invite skepticism. The urate instruction matters: use the highest value ever recorded off urate-lowering therapy, since levels dip during acute flares (urate shifts into the inflamed joint) and a flare-time level misleads. Negative synovial fluid subtracts 2 but does not exclude: sampling error and prior treatment cause false negatives.

Worked Example

First MTP attack (+2), erythema plus cannot bear touch (+2), two episodes each resolving in a week (+2), serum urate 9 (+3): total 9, classifies as gout. Contrast: ankle monoarthritis (+1), one prolonged episode (0), urate 5.5 (0), negative fluid (−2): total −1, not gout: think septic arthritis until proven otherwise, which is the can't-miss mimic. Third: tophus present (+4) plus double contour on ultrasound (+4) = 8 with nothing else: classifies on two findings. I verified the calculator applies the domain caps and the urate negative scoring.

Mimics the Criteria Guard Against

The septic joint is the emergency the criteria exist partly to avoid missing: a low score with a hot single joint means aspirate, culture, and treat as septic until cultures return. For uric-acid context our GFR calculator matters because CKD impairs urate excretion, our BMI calculator tracks the obesity that raises urate, and our blood pressure checker follows the hypertension that travels with hyperuricemia.

From Classification to Treatment

Classifying gout starts lifelong management, beyond flare pills: acute flares get NSAIDs, colchicine, or steroids (ice and rest help), but the disease-modifying move is urate lowering (allopurinol or febuxostat) titrated to keep serum urate under 6 mg/dL (under 5 with tophi), which dissolves crystals over months to years. Start flare prophylaxis (low-dose colchicine) when initiating urate-lowering therapy, since mobilizing urate triggers flares. Lifestyle helps at the margins: weight loss, less beer and fructose, more low-fat dairy and cherries; it rarely suffices alone. Treat-to-target with regular urate checks is the standard the criteria point toward.

Limits of Classification Criteria

These criteria classify established gout for research and support clinical diagnosis; they are not a substitute for arthrocentesis, which remains the diagnostic gold standard. Early disease may not reach 8 points before tophi or erosions develop. Serum urate timing confounds scoring during flares. And classification is not destiny: some 8-point patients have CPPD, which is why crystal analysis of joint fluid stays the tiebreaker whenever the diagnosis changes management.

Recheck urate after addressing the reversible drivers before labeling anyone hyperuricemic: hydration, recent alcohol, and diuretic timing all shift the number.

Asymptomatic Hyperuricemia: Treat or Watch?

High uric acid without gout flares is one of medicine's longest arguments. The criteria do not apply (no entry episode), and guidelines generally advise against urate-lowering drugs for asymptomatic hyperuricemia, with two debated exceptions: very high levels (above ~13 mg/dL in men) where crystal deposition risk climbs, and uric acid kidney stones or tumor lysis risk. The lifestyle advice still holds: weight, beer, fructose, and diuretics raise urate; treating hypertension with losartan (which lowers urate) instead of a thiazide is a neat two-for-one when both conditions coexist. Kidney function deserves monitoring since hyperuricemia predicts CKD progression, though causation is unproven. The key distinction: hyperuricemia is a risk factor, gout is a disease. Do not start lifelong allopurinol for a number; do start the conversation about the habits and medications behind it, and recheck after addressing them.

For informational purposes only, not medical advice. Consult a healthcare professional.