Emergency · LIVE

PECARN pediatric head CT

Apply the Kuppermann 2009 PECARN prediction trees and return high, intermediate, or low risk of clinically important brain injury from caller-assigned findings after pediatric head trauma.

LIVE $0.005 USDC GET /api/calc/pecarn_head

Markdown: /docs/pecarn-head.md · Canonical: https://magentlab.com/docs/pecarn-head

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

What it computes

Apply the Kuppermann 2009 PECARN prediction trees and return high, intermediate, or low risk of clinically important brain injury from caller-assigned findings after pediatric head trauma.

When to use

When an agent has caller-assigned findings after blunt head trauma in a child 0-17 years and needs the Kuppermann 2009 PECARN head CT trees, not Canadian CT Head, CATCH, CHALICE, or NEXUS.

When not to use

• Not a diagnosis of clinically important brain injury. magent does not examine the patient.
• This tool is the Kuppermann 2009 PECARN head CT rule only. It is not Canadian CT Head, not CATCH, not CHALICE, not NEXUS, and not PECARN IAI, febrile infant, or c-spine rules.
• Two mutually exclusive trees: age <2 (lt_2) and age 2-17 (ge_2). Flags that belong to the other age band are required on the API but do not score.
• The caller assigns GCS <=14, altered mental status (agitation, somnolence, repetitive questioning, or slow response), and all other findings. magent does not take a GCS integer and does not classify mechanism or fall height.
• Severe mechanism is caller-assigned. Published list: MVC ejection, rollover, or death of another passenger; unhelmeted pedestrian or bicyclist struck by a motorized vehicle; fall >3 ft if <2 years or >5 ft if >=2 years; head struck by a high-impact object.

Formula

high if any age-applicable high-risk factor, else intermediate if any age-applicable intermediate factor, else low; lt_2 tree if age < 2, ge_2 tree if age 2-17

Citation

Title

Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study

Authors

Kuppermann N, Holmes JF, Dayan PS, et al.

Source

Lancet. 2009;374(9696):1160-1170

DOI

10.1016/S0140-6736(09)61558-0

Worked example

Also searched as

• PECARN head CT
• PECARN pediatric head injury
• Kuppermann 2009
• PECARN ciTBI
• pediatric head trauma CT
• PECARN head trauma algorithm
• children very low risk brain injury
• PECARN under 2 and 2 or older

Try

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

/api/calc/pecarn_head?age=10&gcs_le_14=false&altered_mental_status=false&palpable_skull_fracture=false&signs_basilar_skull_fracture=false&nonfrontal_scalp_hematoma=false&loc_ge_5_seconds=false&not_acting_normally=false&history_of_loc=false&history_of_vomiting=false&severe_headache=false&severe_mechanism=false

Full URL: https://api.magentlab.com/api/calc/pecarn_head?age=10&gcs_le_14=false&altered_mental_status=false&palpable_skull_fracture=false&signs_basilar_skull_fracture=false&nonfrontal_scalp_hematoma=false&loc_ge_5_seconds=false&not_acting_normally=false&history_of_loc=false&history_of_vomiting=false&severe_headache=false&severe_mechanism=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/pecarn_head?age=10&gcs_le_14=false&altered_mental_status=false&palpable_skull_fracture=false&signs_basilar_skull_fracture=false&nonfrontal_scalp_hematoma=false&loc_ge_5_seconds=false&not_acting_normally=false&history_of_loc=false&history_of_vomiting=false&severe_headache=false&severe_mechanism=false"

Parameters

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/pecarn_head 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": "10",
      "altered_mental_status": "false",
      "gcs_le_14": "false",
      "history_of_loc": "false",
      "history_of_vomiting": "false",
      "loc_ge_5_seconds": "false",
      "nonfrontal_scalp_hematoma": "false",
      "not_acting_normally": "false",
      "palpable_skull_fracture": "false",
      "severe_headache": "false",
      "severe_mechanism": "false",
      "signs_basilar_skull_fracture": "false"
    },
    {
      "age": "10",
      "altered_mental_status": "false",
      "gcs_le_14": "false",
      "history_of_loc": "false",
      "history_of_vomiting": "false",
      "loc_ge_5_seconds": "false",
      "nonfrontal_scalp_hematoma": "false",
      "not_acting_normally": "false",
      "palpable_skull_fracture": "false",
      "severe_headache": "false",
      "severe_mechanism": "false",
      "signs_basilar_skull_fracture": "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/pecarn_head",
  "items": [
    {
      "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.",
      "citation": {
        "authors": "Kuppermann N, Holmes JF, Dayan PS, et al.",
        "doi": "10.1016/S0140-6736(09)61558-0",
        "id": "kuppermann-2009",
        "source": "Lancet. 2009;374(9696):1160-1170",
        "title": "Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study"
      },
      "formula": "pecarn_head",
      "formula_expression": "high if any age-applicable high-risk factor, else intermediate if any age-applicable intermediate factor, else low; lt_2 tree if age < 2, ge_2 tree if age 2-17",
      "age_years": 10,
      "criteria": [
        {
          "factor": "gcs_le_14",
          "met": false
        },
        {
          "factor": "altered_mental_status",
          "met": false
        },
        {
          "factor": "signs_basilar_skull_fracture",
          "met": false
        },
        {
          "factor": "history_of_loc",
          "met": false
        },
        {
          "factor": "history_of_vomiting",
          "met": false
        },
        {
          "factor": "severe_headache",
          "met": false
        },
        {
          "factor": "severe_mechanism",
          "met": false
        }
      ],
      "age_band": "ge_2",
      "ct_not_recommended": true,
      "ct_recommended": false,
      "observation_vs_ct": false,
      "risk_tier": "low"
    },
    {
      "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.",
      "citation": {
        "authors": "Kuppermann N, Holmes JF, Dayan PS, et al.",
        "doi": "10.1016/S0140-6736(09)61558-0",
        "id": "kuppermann-2009",
        "source": "Lancet. 2009;374(9696):1160-1170",
        "title": "Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study"
      },
      "formula": "pecarn_head",
      "formula_expression": "high if any age-applicable high-risk factor, else intermediate if any age-applicable intermediate factor, else low; lt_2 tree if age < 2, ge_2 tree if age 2-17",
      "age_years": 10,
      "criteria": [
        {
          "factor": "gcs_le_14",
          "met": false
        },
        {
          "factor": "altered_mental_status",
          "met": false
        },
        {
          "factor": "signs_basilar_skull_fracture",
          "met": false
        },
        {
          "factor": "history_of_loc",
          "met": false
        },
        {
          "factor": "history_of_vomiting",
          "met": false
        },
        {
          "factor": "severe_headache",
          "met": false
        },
        {
          "factor": "severe_mechanism",
          "met": false
        }
      ],
      "age_band": "ge_2",
      "ct_not_recommended": true,
      "ct_recommended": false,
      "observation_vs_ct": false,
      "risk_tier": "low"
    }
  ]
}

Response

Example JSON

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

{
  "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.",
  "citation": {
    "authors": "Kuppermann N, Holmes JF, Dayan PS, et al.",
    "doi": "10.1016/S0140-6736(09)61558-0",
    "id": "kuppermann-2009",
    "source": "Lancet. 2009;374(9696):1160-1170",
    "title": "Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study"
  },
  "formula": "pecarn_head",
  "formula_expression": "high if any age-applicable high-risk factor, else intermediate if any age-applicable intermediate factor, else low; lt_2 tree if age < 2, ge_2 tree if age 2-17",
  "age_years": 10,
  "criteria": [
    {
      "factor": "gcs_le_14",
      "met": false
    },
    {
      "factor": "altered_mental_status",
      "met": false
    },
    {
      "factor": "signs_basilar_skull_fracture",
      "met": false
    },
    {
      "factor": "history_of_loc",
      "met": false
    },
    {
      "factor": "history_of_vomiting",
      "met": false
    },
    {
      "factor": "severe_headache",
      "met": false
    },
    {
      "factor": "severe_mechanism",
      "met": false
    }
  ],
  "age_band": "ge_2",
  "ct_not_recommended": true,
  "ct_recommended": false,
  "observation_vs_ct": false,
  "risk_tier": "low"
}

Client errors (HTTP 400)

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

Related tools

• Canadian CT Head Rule — Apply the Stiell 2001 Canadian CT Head Rule and return whether CT is indicated from caller-assigned high-risk and medium-risk findings after minor blunt head injury.
• Glasgow Coma Scale — Compute the Glasgow Coma Scale as the sum of caller-assigned eye, verbal, and motor integers. The 1974 or 1976 edition is required.

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.