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Centor and McIsaac scores

Compute the Centor score or the McIsaac age-modified score from four caller-assigned pharyngitis findings. The edition is required.

LIVE $0.005 USDC GET /api/calc/centor

Markdown: /docs/centor.md · Canonical: https://magentlab.com/docs/centor

Not a medical device. Not a diagnosis, dose, or listing recommendation.

What it computes

Compute the Centor score or the McIsaac age-modified score from four caller-assigned pharyngitis findings. The edition is required.

When to use

When an agent needs a published Centor or McIsaac total and must not silently pick an edition or invent the four clinical findings.

When not to use

  • Not a test-or-treat protocol and not a diagnosis of streptococcal pharyngitis.
  • The caller assigns the four clinical findings. magent does not examine the throat.
  • McIsaac age bands are 3-14 / 15-44 / >=45 as published. edition is required; magent does not pick Centor or McIsaac.

Formula

McIsaac = Centor criteria + age 3-14 +1, 15-44 0, >=45 -1; max 5

Citation

Title
Empirical validation of guidelines for the management of pharyngitis in children and adults
Authors
McIsaac WJ, Kellner JD, Aufricht P, Vanjaka A, Low DE
Source
JAMA. 2004;291(13):1587-1595
DOI
10.1001/jama.291.13.1587

Worked example

McIsaac adult all-negative

Given: age=30cough_absent=falseedition=mcisaachistory_of_fever=falsetender_anterior_cervical_nodes=falsetonsillar_exudates=false

  1. Four findings absent; age 30 is 15-44 → 0
  2. Score = 0 (max 5)

Centor all four present

Given: cough_absent=trueedition=centorhistory_of_fever=truetender_anterior_cervical_nodes=truetonsillar_exudates=true

  1. Four findings present → 1 each
  2. Score = 4 (max 4)

McIsaac child all-negative

Given: age=8cough_absent=falseedition=mcisaachistory_of_fever=falsetender_anterior_cervical_nodes=falsetonsillar_exudates=false

  1. Four findings absent; age 8 is 3-14 → +1
  2. Score = 1

Try

Opens the live endpoint. Unpaid browser requests show the paywall; agents should send Accept: application/json.

/api/calc/centor?edition=mcisaac&age=30&tonsillar_exudates=false&tender_anterior_cervical_nodes=false&history_of_fever=false&cough_absent=false

Full URL: https://api.magentlab.com/api/calc/centor?edition=mcisaac&age=30&tonsillar_exudates=false&tender_anterior_cervical_nodes=false&history_of_fever=false&cough_absent=false

x402 V2 curl

Expect HTTP 402 and a PAYMENT-REQUIRED header until you retry with PAYMENT-SIGNATURE. Incomplete query params return HTTP 400 before any quote or charge. HTTP 503 after a signature: retry the same PAYMENT-SIGNATURE — that is not a new 402. 

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/centor?edition=mcisaac&age=30&tonsillar_exudates=false&tender_anterior_cervical_nodes=false&history_of_fever=false&cough_absent=false"

Cursor mcp.json

Intended config for @magent/mcp. This is not npm @x402/fetch (a payment fetch wrapper). 

{
  "mcpServers": {
    "magent": {
      "args": [
        "-y",
        "@magent/mcp"
      ],
      "command": "npx",
      "env": {
        "X402_PRIVATE_KEY": "0xYOUR_SPENDING_KEY"
      }
    }
  }
}

Parameters

Name Type Required Description
edition string required · centor, mcisaac Published score. Required; magent does not pick Centor (four findings, max 4) or McIsaac (age-modified, max 5).
age integer optional Age in years (3-120). Required when edition=mcisaac (3-14 +1, 15-44 0, >=45 -1). Ignored when edition=centor.
tonsillar_exudates boolean required Tonsillar exudates. true or false as assigned by the caller.
tender_anterior_cervical_nodes boolean required Tender anterior cervical nodes. true or false as assigned by the caller.
history_of_fever boolean required History of fever. true or false as assigned by the caller.
cough_absent boolean required Absence of cough. true when cough is absent; false when cough is present.

Bulk (POST)

POST the same path with a JSON items array. Price is n times the GET unit. Invalid items return HTTP 400 before settlement.

POST /api/calc/centor Max 25 unit_amount * n PREVIEW

  • 1 to 25 items. Each item uses the same keys as the GET query parameters.
  • The first invalid item fails the whole request (index in the 400 JSON). You are not charged.
  • HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row.
  • Catalog misses (empty matches, found=false) stay paid 200s inside that slot.
  • x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items.

Example request (fixture)

{
  "items": [
    {
      "age": "30",
      "cough_absent": "false",
      "edition": "mcisaac",
      "history_of_fever": "false",
      "tender_anterior_cervical_nodes": "false",
      "tonsillar_exudates": "false"
    },
    {
      "age": "30",
      "cough_absent": "false",
      "edition": "mcisaac",
      "history_of_fever": "false",
      "tender_anterior_cervical_nodes": "false",
      "tonsillar_exudates": "false"
    }
  ]
}

Open bulk paywall →

Opens a two-item fixture on the API host. Unpaid browsers get the same MetaMask paywall as GET; Pay retries POST with those items.

Example 200 (fixture)

{
  "count": 2,
  "path": "/api/calc/centor",
  "items": [
    {
      "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.",
      "age_years": 30,
      "citation": {
        "authors": "McIsaac WJ, Kellner JD, Aufricht P, Vanjaka A, Low DE",
        "doi": "10.1001/jama.291.13.1587",
        "id": "mcisaac-2004",
        "source": "JAMA. 2004;291(13):1587-1595",
        "title": "Empirical validation of guidelines for the management of pharyngitis in children and adults"
      },
      "formula": "mcisaac",
      "formula_expression": "McIsaac = Centor criteria + age 3-14 +1, 15-44 0, >=45 -1; max 5",
      "max_score": 5,
      "score": 0,
      "edition": "mcisaac"
    },
    {
      "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.",
      "age_years": 30,
      "citation": {
        "authors": "McIsaac WJ, Kellner JD, Aufricht P, Vanjaka A, Low DE",
        "doi": "10.1001/jama.291.13.1587",
        "id": "mcisaac-2004",
        "source": "JAMA. 2004;291(13):1587-1595",
        "title": "Empirical validation of guidelines for the management of pharyngitis in children and adults"
      },
      "formula": "mcisaac",
      "formula_expression": "McIsaac = Centor criteria + age 3-14 +1, 15-44 0, >=45 -1; max 5",
      "max_score": 5,
      "score": 0,
      "edition": "mcisaac"
    }
  ]
}

Response

Field Type Description
formula string centor or mcisaac
formula_expression string Exact expression used
edition string centor or mcisaac
score integer Total points (0-4 Centor; -1 to 5 McIsaac)
max_score integer 4 (Centor) or 5 (McIsaac)
age_years integer Age used for McIsaac bands. Present when edition=mcisaac.
components array Per-finding points
citation object Centor 1981 or McIsaac 2004
disclaimer string Not-a-device notice

Example JSON

Machine form of the same example. Frozen fixture. Not a live lookup. 

{
  "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.",
  "age_years": 30,
  "citation": {
    "authors": "McIsaac WJ, Kellner JD, Aufricht P, Vanjaka A, Low DE",
    "doi": "10.1001/jama.291.13.1587",
    "id": "mcisaac-2004",
    "source": "JAMA. 2004;291(13):1587-1595",
    "title": "Empirical validation of guidelines for the management of pharyngitis in children and adults"
  },
  "formula": "mcisaac",
  "formula_expression": "McIsaac = Centor criteria + age 3-14 +1, 15-44 0, >=45 -1; max 5",
  "max_score": 5,
  "score": 0,
  "edition": "mcisaac"
}

Errors

HTTP Code When
400 invalid_centor_edition edition must be centor or mcisaac. Returned before settlement; you are not charged.
400 invalid_flag boolean clinical flags must be true or false Returned before settlement; you are not charged.
400 invalid_centor_age age must be an integer from 3 to 120 (McIsaac). Returned before settlement; you are not charged.
400 invalid_items POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
400 invalid_item_count items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
400 invalid_item each items entry must be a JSON object Returned before settlement; you are not charged.
402 payment_required Missing or invalid PAYMENT-SIGNATURE; decode the PAYMENT-REQUIRED header
409 payment_in_progress The same authorization nonce is already being settled; retry shortly
429 rate_limited Too many requests from this client
503 settlement_uncertain Settlement is unconfirmed; retry with the same PAYMENT-SIGNATURE
503 settle_failed Settlement failed; retry with the same PAYMENT-SIGNATURE shortly
503 facilitator_unavailable Payment facilitator unavailable
503 facilitator_misconfigured Payment facilitator is not configured
503 facilitator_unauthorized Payment facilitator rejected credentials
503 ledger_unavailable Payment ledger unavailable
503 payment_unavailable Payment processing unavailable

Related tools

  • CURB-65 — Compute the CURB-65 community-acquired pneumonia severity score from age and discrete flags.

Also searched as

  • Centor score
  • McIsaac score
  • modified Centor score
  • strep pharyngitis score
  • streptococcal pharyngitis criteria
  • tonsillar exudates tender nodes

Payment

Required query parameters must be present and valid. Invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s. Unpaid valid requests return HTTP 402 with a base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote: retry the same PAYMENT-SIGNATURE. Full handshake and shared payment errors: Payments.

Guarantees

  • Invalid query parameters return HTTP 400 before settlement. You are not charged.
  • Settlement finishes before the tool executes (paymentFlow upfront). Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE.
  • HTTP 402 is unpaid only. Do not sign a second authorization because of a 503.
  • Execution is timeout-bounded and concurrency-capped.
  • Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.