Gout Diagnosis Score Calculator

This page applies the seven-item Janssens clinical rule developed to estimate the probability of gout in adults with acute monoarthritis when joint-fluid microscopy is not immediately available. It adds points for sex, attack history, rapid onset, redness, first metatarsophalangeal joint involvement, selected cardiovascular history and serum urate. Despite the familiar page title, the result is not a diagnosis.

A hot, swollen joint can have several causes. Septic arthritis is an emergency and can resemble gout; a score must never delay urgent assessment or aspiration when infection is possible. The original rule was developed in primary care and later validated in particular patient groups. Its performance may differ outside those settings or when questions are interpreted differently.

Select yes or no for each feature exactly as defined in the published rule. The page assigns the listed points and returns the sum from 0 to 13. Read the probability band only as the rule’s triage category.

1. Choose male sex only when that category matches the patient information used by the original rule.
2. Mark whether there has been a previous patient-reported arthritis attack.
3. Mark onset within one day, visible joint redness and involvement of the first metatarsophalangeal joint at the base of the big toe.
4. Mark the cardiovascular item when hypertension or at least one relevant cardiovascular condition is present. The original publication describes hypertension or one or more cardiovascular diseases.
5. Use yes for serum uric acid above 5.88 mg/dL, equivalent to 0.35 mmol/L. Use an appropriately timed laboratory result and do not confuse mg/dL with mmol/L.

The calculator does not ask about fever, immune suppression, recent surgery, prosthetic joints or other urgent infection clues. Those omissions are a reason to assess the patient, not evidence that those factors are unimportant.

A low score makes gout less likely under this rule, while a high score makes it more likely; the intermediate range leaves substantial uncertainty. The original study reported probability estimates for its population, but those numbers should not be automatically transferred to every setting. Prevalence, referral patterns and case selection affect predictive value.

Definitive evaluation may include clinical examination and, where appropriate, synovial-fluid analysis for monosodium urate crystals and infection. Serum urate alone is not diagnostic: it can be normal during an acute flare, and many people with an elevated level do not have gout. Seek urgent medical care for a severely painful hot joint with fever, systemic illness, rapidly spreading redness, immune suppression or concern for infection.