# Centor / McIsaac Streptococcal Pharyngitis Score

> Centor / McIsaac Streptococcal Pharyngitis Score is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Calculates the Centor or age-modified McIsaac score for estimating streptococcal pharyngitis likelihood from four clinical findings

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/centor
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/centor-mcisaac-streptococcal-pharyngitis-score-4097c933
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zteSylTgqzMdlnlLTCVtb

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 centor-mcisaac-streptococcal-pharyngitis-score-4097c933
```

Example prompt: Calculate the McIsaac strep score for a 10-year-old patient who has tonsillar exudates, tender anterior cervical nodes, and a history of fever, but is still coughing — use edition mcisaac.

## When to prefer this

Use this endpoint when you need a deterministic, citable Centor or McIsaac strep score computed from four caller-assigned clinical findings. It is the right choice when you want an auditable, published-guideline score (not a test-or-treat recommendation), especially in EHR automation, clinical decision support, or triage workflows where you must explicitly select the scoring edition. Prefer the McIsaac edition for pediatric patients (ages 3–14 receive a +1 point adjustment). This endpoint does not interpret findings or recommend testing — the caller is responsible for assigning the clinical findings.

## Known failure modes

- Missing required 'edition' parameter returns an error — caller must explicitly choose centor or mcisaac
- Missing 'age' when edition=mcisaac returns an error — age is required for the age-adjustment step
- Invalid boolean values for clinical findings cause schema validation failure
- Age outside valid range (below 3 or above 120) may be rejected or produce an unexpected result
- Payment failure (x402 protocol) blocks the request if USDC balance is insufficient

## How this service works

Centor or McIsaac (age-modified) score for streptococcal pharyngitis from four caller-assigned findings. edition=centor (max 4) or edition=mcisaac (age 3-14 +1, 15-44 0, >=45 -1, max 5) is required; magent does not pick one. Deterministic published score with citation; not a test-or-treat protocol.

## Output

Returns the integer Centor or McIsaac score (0–4 for Centor, 0–5 for McIsaac) along with an interpretive note and the published citation (Centor 1981 or McIsaac 1998/2000), enabling downstream risk stratification for streptococcal pharyngitis.

## 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": [
      "edition",
      "tonsillar_exudates",
      "tender_anterior_cervical_nodes",
      "history_of_fever",
      "cough_absent"
     ],
     "properties": {
      "age": {
       "type": "integer",
       "description": "Age in years (3-120). Required when edition=mcisaac (3-14 +1, 15-44 0, >=45 -1). Ignored when edition=centor."
      },
      "edition": {
       "enum": [
        "centor",
        "mcisaac"
       ],
       "type": "string",
       "description": "Published score. Required; magent does not pick Centor (four findings, max 4) or McIsaac (age-modified, max 5)."
      },
      "cough_absent": {
       "type": "boolean",
       "description": "Absence of cough. true when cough is absent; false when cough is present."
      },
      "history_of_fever": {
       "type": "boolean",
       "description": "History of fever. true or false as assigned by the caller."
      },
      "tonsillar_exudates": {
       "type": "boolean",
       "description": "Tonsillar exudates. true or false as assigned by the caller."
      },
      "tender_anterior_cervical_nodes": {
       "type": "boolean",
       "description": "Tender anterior cervical nodes. true or false as assigned by the caller."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "path": "/api/calc/centor",
  "count": 2,
  "items": [
   {
    "score": 0,
    "edition": "mcisaac",
    "formula": "mcisaac",
    "citation": {
     "id": "mcisaac-2004",
     "doi": "10.1001/jama.291.13.1587",
     "title": "Empirical validation of guidelines for the management of pharyngitis in children and adults",
     "source": "JAMA. 2004;291(13):1587-1595",
     "authors": "McIsaac WJ, Kellner JD, Aufricht P, Vanjaka A, Low DE"
    },
    "age_years": 30,
    "max_score": 5,
    "components": [
     {
      "factor": "tonsillar_exudates",
      "points": 0,
      "present": false
     },
     {
      "factor": "tender_anterior_cervical_nodes",
      "points": 0,
      "present": false
     },
     {
      "factor": "history_of_fever",
      "points": 0,
      "present": false
     },
     {
      "factor": "cough_absent",
      "points": 0,
      "present": false
     },
     {
      "value": 30,
      "factor": "age_adjustment",
      "points": 0,
      "present": false
     }
    ],
    "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
    "formula_expression": "McIsaac = Centor criteria + age 3-14 +1, 15-44 0, >=45 -1; max 5"
   },
   {
    "score": 0,
    "edition": "mcisaac",
    "formula": "mcisaac",
    "citation": {
     "id": "mcisaac-2004",
     "doi": "10.1001/jama.291.13.1587",
     "title": "Empirical validation of guidelines for the management of pharyngitis in children and adults",
     "source": "JAMA. 2004;291(13):1587-1595",
     "authors": "McIsaac WJ, Kellner JD, Aufricht P, Vanjaka A, Low DE"
    },
    "age_years": 30,
    "max_score": 5,
    "components": [
     {
      "factor": "tonsillar_exudates",
      "points": 0,
      "present": false
     },
     {
      "factor": "tender_anterior_cervical_nodes",
      "points": 0,
      "present": false
     },
     {
      "factor": "history_of_fever",
      "points": 0,
      "present": false
     },
     {
      "factor": "cough_absent",
      "points": 0,
      "present": false
     },
     {
      "value": 30,
      "factor": "age_adjustment",
      "points": 0,
      "present": false
     }
    ],
    "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submis
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/centor-mcisaac-streptococcal-pharyngitis-score-4097c933/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.magentlab.com](https://www.zero.xyz/host/api.magentlab.com/llms.txt)