The Jones criteria diagnose acute rheumatic fever (ARF) using combinations of major and minor manifestations plus evidence of preceding group A streptococcal (GAS) infection.

Risk-stratified major and minor criteria (AHA 2015, WHO/CDC/Australian tables):

	Low-risk populations	Moderate/high-risk populations
Major manifestations	Carditis (clinical or subclinical); polyarthritis; chorea; erythema marginatum; subcutaneous nodules.	Carditis (clinical or subclinical); monoarthritis or polyarthritis; polyarthralgia; chorea; erythema marginatum; subcutaneous nodules.
Minor manifestations	Polyarthralgia; fever ≥38.5°C; ESR ≥60 mm/h and/or CRP ≥30 mg/L; prolonged PR interval on ECG (age-adjusted).	Monoarthralgia; fever ≥38.0°C; ESR ≥30 mm/h and/or CRP ≥30 mg/L; prolonged PR interval on ECG (age-adjusted).

Diagnostic combinations implemented in this calculator (definite initial ARF):

Evidence of preceding GAS infection plus either:
- ≥2 major manifestations; or
- 1 major and ≥2 minor manifestations.

This calculator counts user-selected major and minor manifestations, then encodes the initial-episode Jones combinations together with GAS evidence via an internal score. A high internal score corresponds exactly to meeting the above combinations with documented antecedent GAS infection. Recurrent-episode pathways (including diagnosis on 3 minor manifestations alone) and exceptions such as isolated Sydenham chorea or indolent carditis are not fully modelled and require guideline-based clinical judgement.

Jones Criteria for Acute Rheumatic Fever Diagnosis