# CRB-65 Score Calculator (Lim 2003)

> CRB-65 Score Calculator (Lim 2003) 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).

Computes the CRB-65 pneumonia severity score (0–4) from caller-assessed confusion, respiratory rate, blood pressure, and age flags

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/crb65
- 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/crb-65-score-calculator-lim-2003-fc868db3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6-OAsAfSOW5ZEwh28J8G2

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 crb-65-score-calculator-lim-2003-fc868db3
```

Example prompt: Calculate the CRB-65 score for a 72-year-old patient who has new confusion, a respiratory rate of 32 breaths per minute, and a systolic blood pressure of 85 mmHg — confusion is present, respiratory rate is flagged high, and blood pressure is flagged low.

## When to prefer this

Use this endpoint when you need a rapid CRB-65 score (Lim 2003) and BUN/urea is unavailable or impractical — it is the urea-free alternative to CURB-65 and is well-suited for primary care and community settings. Prefer it over manual computation when embedding clinical decision support in automated EHR workflows, triage agents, or audit pipelines. The caller must pre-classify the C, R, and B flags before calling; the API does not accept raw vital-sign numbers for BP or convert BUN values.

## Known failure modes

- Missing required query parameters (age, confusion, respiratory_rate_ge_30, low_blood_pressure) returns a 4xx error
- Age outside 18–120 range may be rejected or produce unexpected output
- Passing continuous BP values instead of a pre-computed boolean for low_blood_pressure will cause an error — the API does not accept raw BP numbers
- Confusing this endpoint with CURB-65 (which requires urea/BUN) will produce an incomplete query

## How this service works

Lim 2003 CRB-65 for community-acquired pneumonia: confusion, respiratory rate ≥30/min, low blood pressure (SBP <90 or DBP ≤60), and age ≥65; 1 point each, max 4. No urea. Score only; no mortality percentages or site-of-care bands. Not a diagnosis. Not CURB-65. Caller assigns the C, R, and B flags; magent does not convert BUN or take BP numbers.

## Output

Returns a CRB-65 integer score from 0 to 4, calculated as one point each for: new confusion (caller-assigned), respiratory rate ≥30/min (caller-assigned), low blood pressure — SBP <90 or DBP ≤60 (caller-assigned), and age ≥65 (derived from the provided age). No mortality percentages or site-of-care recommendations are included; this is a raw score only.

## 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": [
      "age",
      "confusion",
      "respiratory_rate_ge_30",
      "low_blood_pressure"
     ],
     "properties": {
      "age": {
       "type": "integer",
       "description": "Age in years (18-120). Age ≥65 scores 1."
      },
      "confusion": {
       "type": "boolean",
       "description": "New confusion (C) as assigned by the caller. true or false."
      },
      "low_blood_pressure": {
       "type": "boolean",
       "description": "SBP <90 mmHg or DBP ≤60 mmHg (B) as assigned by the caller. true or false. magent does not take BP numbers."
      },
      "respiratory_rate_ge_30": {
       "type": "boolean",
       "description": "Respiratory rate ≥30/min (R) as assigned by the caller. true or false."
      }
     }
    }
   },
   "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/crb65",
  "count": 2,
  "items": [
   {
    "score": 0,
    "formula": "crb65",
    "citation": {
     "id": "lim-2003",
     "doi": "10.1136/thorax.58.5.377",
     "title": "Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study",
     "source": "Thorax. 2003;58(5):377-382",
     "authors": "Lim WS, van der Eerden MM, Laing R, et al."
    },
    "age_years": 40,
    "max_score": 4,
    "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.",
    "formula_expression": "CRB-65 = confusion + respiratory_rate_ge_30 + low_blood_pressure + age_ge_65; max 4"
   },
   {
    "score": 0,
    "formula": "crb65",
    "citation": {
     "id": "lim-2003",
     "doi": "10.1136/thorax.58.5.377",
     "title": "Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study",
     "source": "Thorax. 2003;58(5):377-382",
     "authors": "Lim WS, van der Eerden MM, Laing R, et al."
    },
    "age_years": 40,
    "max_score": 4,
    "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.",
    "formula_expression": "CRB-65 = confusion + respiratory_rate_ge_30 + low_blood_pressure + age_ge_65; max 4"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/crb-65-score-calculator-lim-2003-fc868db3/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)