CRB-65 community-acquired pneumonia

CRB-65

Compute the Lim 2003 CRB-65 community-acquired pneumonia score from age and caller-assigned confusion, respiratory-rate, and blood-pressure flags. Urea is not an input.

LIVE $0.005 USDC GET /api/calc/crb65

Markdown: /docs/crb-65.md · Canonical: https://magentlab.com/docs/crb-65

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

What it computes

Compute the Lim 2003 CRB-65 community-acquired pneumonia score from age and caller-assigned confusion, respiratory-rate, and blood-pressure flags. Urea is not an input.

When to use

When an agent needs the published CRB-65 total (no urea) and must not substitute CURB-65 or invent site-of-care advice.

When not to use

Not a diagnosis and not a site-of-care decision.
This is CRB-65 (no urea), not CURB-65. magent does not convert BUN.
The caller assigns confusion, respiratory_rate_ge_30, and low_blood_pressure flags the same way as CURB-65.

Formula

CRB-65 = confusion + respiratory_rate_ge_30 + low_blood_pressure + age_ge_65; max 4

Citation

Title: Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study
Authors: Lim WS, van der Eerden MM, Laing R, et al.
Source: Thorax. 2003;58(5):377-382
DOI: 10.1136/thorax.58.5.377

Worked example

Age 40, all flags false

Given: age=40confusion=falselow_blood_pressure=falserespiratory_rate_ge_30=false

Confusion false → 0; respiratory_rate_ge_30 false → 0; low_blood_pressure false → 0; age 40 is not ≥65 → 0
Score = 0 (max 4)

Age 70 and confusion

Given: age=70confusion=truelow_blood_pressure=falserespiratory_rate_ge_30=false

Confusion → 1; age ≥65 → 1
Score = 2 (max 4)

Also searched as

CRB 65
CRB65
CRB-65 score
Lim CRB-65
CAP CRB-65

Try

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

/api/calc/crb65?age=40&confusion=false&respiratory_rate_ge_30=false&low_blood_pressure=false

Full URL: https://api.magentlab.com/api/calc/crb65?age=40&confusion=false&respiratory_rate_ge_30=false&low_blood_pressure=false

Call

Expect HTTP 402 until you retry with PAYMENT-SIGNATURE. Incomplete query params return HTTP 400 before any quote or charge.

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/crb65?age=40&confusion=false&respiratory_rate_ge_30=false&low_blood_pressure=false"

Parameters

Name	Type	Required	Description
`age`	integer	required	Age in years (18-120). Age ≥65 scores 1.
`confusion`	boolean	required	New confusion (C) as assigned by the caller. true or false.
`respiratory_rate_ge_30`	boolean	required	Respiratory rate ≥30/min (R) as assigned by the caller. true or false.
`low_blood_pressure`	boolean	required	SBP <90 mmHg or DBP ≤60 mmHg (B) as assigned by the caller. true or false. magent does not take BP numbers.

Bulk (POST)

POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement.

POST /api/calc/crb65 Max 25 unit_amount + extra_item_amount * (n - 1) extra $0.002 PREVIEW

1 to 25 items. Each item uses the same keys as the GET query parameters.
POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows.
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": "40",
      "confusion": "false",
      "low_blood_pressure": "false",
      "respiratory_rate_ge_30": "false"
    },
    {
      "age": "40",
      "confusion": "false",
      "low_blood_pressure": "false",
      "respiratory_rate_ge_30": "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/crb65",
  "items": [
    {
      "components": [
        {
          "factor": "confusion",
          "points": 0,
          "present": false
        },
        {
          "factor": "respiratory_rate_ge_30",
          "points": 0,
          "present": false
        },
        {
          "factor": "low_blood_pressure",
          "points": 0,
          "present": false
        },
        {
          "value": 40,
          "factor": "age_ge_65",
          "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": 40,
      "citation": {
        "authors": "Lim WS, van der Eerden MM, Laing R, et al.",
        "doi": "10.1136/thorax.58.5.377",
        "id": "lim-2003",
        "source": "Thorax. 2003;58(5):377-382",
        "title": "Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study"
      },
      "formula": "crb65",
      "formula_expression": "CRB-65 = confusion + respiratory_rate_ge_30 + low_blood_pressure + age_ge_65; max 4",
      "max_score": 4,
      "score": 0
    },
    {
      "components": [
        {
          "factor": "confusion",
          "points": 0,
          "present": false
        },
        {
          "factor": "respiratory_rate_ge_30",
          "points": 0,
          "present": false
        },
        {
          "factor": "low_blood_pressure",
          "points": 0,
          "present": false
        },
        {
          "value": 40,
          "factor": "age_ge_65",
          "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": 40,
      "citation": {
        "authors": "Lim WS, van der Eerden MM, Laing R, et al.",
        "doi": "10.1136/thorax.58.5.377",
        "id": "lim-2003",
        "source": "Thorax. 2003;58(5):377-382",
        "title": "Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study"
      },
      "formula": "crb65",
      "formula_expression": "CRB-65 = confusion + respiratory_rate_ge_30 + low_blood_pressure + age_ge_65; max 4",
      "max_score": 4,
      "score": 0
    }
  ]
}

Response

Field	Type	Description
`formula`	string	crb65
`formula_expression`	string	Exact expression used
`score`	integer	Total points 0-4
`max_score`	integer	Always 4
`age_years`	integer	Age used for the 65 criterion
`components`	array	Per-factor points
`citation`	object	Thorax 2003 citation
`disclaimer`	string	Not-a-device notice

Example JSON

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

{
  "components": [
    {
      "factor": "confusion",
      "points": 0,
      "present": false
    },
    {
      "factor": "respiratory_rate_ge_30",
      "points": 0,
      "present": false
    },
    {
      "factor": "low_blood_pressure",
      "points": 0,
      "present": false
    },
    {
      "value": 40,
      "factor": "age_ge_65",
      "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": 40,
  "citation": {
    "authors": "Lim WS, van der Eerden MM, Laing R, et al.",
    "doi": "10.1136/thorax.58.5.377",
    "id": "lim-2003",
    "source": "Thorax. 2003;58(5):377-382",
    "title": "Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study"
  },
  "formula": "crb65",
  "formula_expression": "CRB-65 = confusion + respiratory_rate_ge_30 + low_blood_pressure + age_ge_65; max 4",
  "max_score": 4,
  "score": 0
}

Client errors (HTTP 400)

Invalid params return 400 without charge. Shared HTTP 402 and 503 meanings: Payments.

HTTP	Code	When
400	`invalid_age`	age must be an integer from 18 to 120 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_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.

Related tools

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

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. Stdio MCP: /docs/mcp.

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.