# magent Jones Criteria for Acute Rheumatic Fever (Gewitz 2015)

> magent Jones Criteria for Acute Rheumatic Fever (Gewitz 2015) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Applies the 2015 AHA/Gewitz revised Jones criteria (Table 7) to classify whether a patient meets diagnostic criteria for acute rheumatic fever (ARF) based on caller-assigned clinical findings and population risk stratum.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/jones
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/magent-jones-criteria-for-acute-rheumatic-fever-gewitz-2015-a6641c70
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ZX_dFymSP1pZmhDcB5wIF

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability magent-jones-criteria-for-acute-rheumatic-fever-gewitz-2015-a6641c70
```

Example prompt: Apply the 2015 Gewitz Jones criteria for an initial ARF episode in a low-risk population: the patient has confirmed preceding GAS infection, clinical carditis (true), polyarthritis (true), no chorea, no erythema marginatum, no subcutaneous nodules, fever ≥38.5°C (true), fever ≥38.0°C (true), ESR/CRP ≥60 or CRP ≥3 (true), ESR ≥30 or CRP ≥3 (true), and prolonged PR interval (false) — does this child meet Jones criteria for ARF?

## When to prefer this

Use this endpoint when you need a fast, rule-based application of the 2015 AHA/Gewitz revised Jones criteria to caller-assigned findings, particularly when population risk stratification (low vs moderate/high) affects arthritis vs arthralgia and fever threshold eligibility. Prefer this over manual Jones scoring when building clinical decision support tools, EHR integrations, or automated cardiology/rheumatology workflows. Not suitable as a replacement for clinical judgment, echocardiography interpretation, or ECG reading — the caller must supply all findings.

## Known failure modes

- Missing required query parameters returns a validation error
- Invalid enum values for episode or population_risk return a 400-level error
- Contradictory inputs (e.g., joints counted in both major and minor) may produce unexpected scoring — caller must ensure mutual exclusivity
- prolonged_pr set to true with carditis true: PR is silently excluded from minor count per Jones rules
- Incorrect population_risk stratum leads to wrong fever and ESR/CRP threshold application
- Not a diagnosis — result is a criterion-matching flag, not a clinical determination

## How this service works

Gewitz 2015 AHA Jones criteria (Table 7). jones_arf iff evidence_of_preceding_gas and the episode rule: initial 2 major or 1 major plus 2 minor; recurrent also allows 3 minor. Majors/minors follow population_risk for arthritis vs arthralgia, fever, and ESR/CRP. Prolonged PR does not count with carditis. Joints count in major or minor, not both. magent does not examine the patient or read an echocardiogram. Not Jones 1944. Not a diagnosis. Not a medical device.

## Output

Returns a jones_arf boolean indicating whether the patient meets the 2015 AHA/Gewitz Jones criteria for acute rheumatic fever, along with counts and eligibility flags for each major and minor criterion applied under the specified population risk stratum and episode type. Accounts for rules such as: joints counting in major or minor but not both, prolonged PR excluded when carditis is present, and fever and ESR/CRP thresholds varying by population risk.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "queryParams": {
     "type": "object",
     "required": [
      "episode",
      "population_risk",
      "evidence_of_preceding_gas",
      "carditis",
      "polyarthritis",
      "monoarthritis",
      "polyarthralgia",
      "monoarthralgia",
      "chorea",
      "erythema_marginatum",
      "subcutaneous_nodules",
      "fever_ge_38_5",
      "fever_ge_38",
      "esr_ge_60_or_crp_ge_3",
      "esr_ge_30_or_crp_ge_3",
      "prolonged_pr"
     ],
     "properties": {
      "chorea": {
       "type": "boolean",
       "description": "Sydenham chorea as assigned by the caller (Gewitz 2015 major). true or false. magent does not examine the patient."
      },
      "episode": {
       "enum": [
        "initial",
        "recurrent"
       ],
       "type": "string",
       "description": "ARF episode: initial or recurrent (Gewitz 2015 Table 7). Recurrent also allows 3 minor manifestations. magent does not date prior ARF."
      },
      "carditis": {
       "type": "boolean",
       "description": "Clinical and/or subclinical carditis as assigned by the caller (subclinical = echocardiographic valvulitis). Counts as one major. When true, prolonged_pr does not count as a minor. magent does not examine the patient or read an echocardiogram."
      },
      "fever_ge_38": {
       "type": "boolean",
       "description": "Fever ≥38.0 C as assigned by the caller. Counts as a minor only when population_risk is moderate_high. Ignored for counting when population_risk is low. magent does not measure temperature."
      },
      "prolonged_pr": {
       "type": "boolean",
       "description": "Prolonged PR interval as assigned by the caller. Counts as a minor only when carditis is false. magent does not interpret an electrocardiogram."
      },
      "fever_ge_38_5": {
       "type": "boolean",
       "description": "Fever ≥38.5 C as assigned by the caller. Counts as a minor only when population_risk is low. Ignored for counting when population_risk is mo
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/magent-jones-criteria-for-acute-rheumatic-fever-gewitz-2015-a6641c70/health.json
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