The Acute Gout Diagnosis Rule evaluates the likelihood of an acute gout diagnosis based on specific symptoms and medical history. It assesses several factors through yes or no responses, which are converted into a numerical score. This score then corresponds to a prevalence percentage that reflects the likelihood of having gout.

The user inputs include:

- Male sex
- Previous patient-reported arthritis attack
- Onset within 1 day
- Joint redness
- First metatarsophalangeal joint involvement (a common site for gout)
- History of cardiovascular or related conditions (such as hypertension or angina)
- Serum uric acid level greater than 5.88 mg/dL (or 0.35 mmol/L)

For each condition checked as true, specific points are assigned:

- Male sex: 2 points
- Previous arthritis attack: 2 points
- Onset within 1 day: 0.5 points
- Joint redness: 1 point
- First metatarsophalangeal joint involvement: 2.5 points
- Cardiovascular or related conditions: 1.5 points
- High serum uric acid: 3.5 points

The responses are evaluated by adding up the respective points for each true response. The total score, ranging from 0 to 13, determines the interpretation:

- A score of 4 or less suggests that the prevalence of gout is about 2.2%, indicating a low likelihood of gout.
- A score between 5 and 7 suggests a 31.2% prevalence, indicating a moderate likelihood of the condition.
- A score of 8 or more suggests an 80.4% prevalence, indicating a high probability of having gout.

These outcomes help in estimating the likelihood of acute gout based on common symptoms and clinical markers.

The Acute Gout Diagnosis Rule is a clinical calculator used to diagnose acute gout without joint fluid analysis. This rule applies to adult patients presenting with monoarthritis, where only one joint is inflamed. 

The clinical utility of this calculator is to help clinicians make a diagnosis of acute gout in settings where joint fluid analysis may not be readily available or feasible. It uses a combination of clinical factors and laboratory results to determine the likelihood of a gout flare. 

Exclusion criteria for the use of this calculator include patients with polyarticular disease (more than one joint affected), septic arthritis, recent trauma to the joint, or other clear causes of monoarthritis. It should also not be used in patients who have already been diagnosed with gout or pseudogout.