How this calculator works
Seven findings contribute their original weights. The rule was derived in primary-care monoarthritis using joint-fluid crystals as the reference. It estimates a probability band and does not confirm gout or exclude septic arthritis. An acutely hot swollen joint needs clinical assessment. The result is an estimate for information only and is not medical advice.
Formula
Score = 2(male sex) + 2(previous attack) + 0.5(onset within one day) + 1(redness) + 2.5(first MTP involvement) + 1.5(hypertension or cardiovascular disease) + 3.5(urate above the threshold). Each finding is 0 or 1.
Worked example
Male sex, rapid onset and first MTP involvement give 2 + 0.5 + 2.5 = 5, an intermediate band. Adding elevated urate gives 8.5, a high band. All seven findings give 13.
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Frequently asked questions
Which cardiovascular conditions count?
The original history includes hypertension or at least one of angina, myocardial infarction, heart failure, stroke, transient ischaemic attack or peripheral vascular disease.
Where are the band boundaries?
A score of 4 or less is low, above 4 but below 8 intermediate, and 8 or more high. They are study probability bands, not definitive diagnoses.
Can high urate alone diagnose gout?
No. It contributes 3.5 points. Crystal analysis or further investigation may still be needed, particularly when infection is possible.