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PECARN febrile infant rule

PECARN febrile infant

Apply the Kuppermann 2019 PECARN clinical prediction rule and return low_risk only when a febrile infant 60 days or younger has a caller-assigned negative urinalysis, ANC ≤4090/µL, and serum procalcitonin ≤1.71 ng/mL.

LIVE $0.005 USDC GET /api/calc/pecarn_febrile

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

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

What it computes

Apply the Kuppermann 2019 PECARN clinical prediction rule and return low_risk only when a febrile infant 60 days or younger has a caller-assigned negative urinalysis, ANC ≤4090/µL, and serum procalcitonin ≤1.71 ng/mL.

When to use

When an agent already has age in days, a caller-assigned negative or positive urinalysis, ANC, and serum procalcitonin and needs the published three-variable low-risk boolean. magent does not assay UA, ANC, or PCT. Not Rochester, Boston, Philadelphia, Step-by-Step, or pecarn-head.

When not to use

• Not a medical device.
• Not a diagnosis of serious bacterial infection (SBI) and not a discharge, admission, or lumbar-puncture order.
• This tool is the Kuppermann 2019 three-variable PECARN rule only. Not Rochester, Boston, Philadelphia, or Step-by-Step criteria. Not the later AAP/PECARN neonatal cutoffs (ANC 4000 / PCT 0.5). Not pecarn-head.
• Age 0-60 days pins the published population (febrile infants 60 days and younger). Age is required but was not retained in the 3-variable tree.
• magent does not assay urinalysis, ANC, or procalcitonin. The caller assigns negative_urinalysis and laboratory values.

Formula

low_risk iff negative_urinalysis and anc_per_ul <= 4090 and pct_ng_ml <= 1.71; age_days 0-60 pins the published population and is not a tree variable (Kuppermann 2019)

Citation

Title

A Clinical Prediction Rule to Identify Febrile Infants 60 Days and Younger at Low Risk for Serious Bacterial Infections.

Authors

Kuppermann N, Dayan PS, Levine DA, et al.

Source

JAMA Pediatr. 2019;173(4):342-351

DOI

10.1001/jamapediatrics.2018.5501

Worked example

Also searched as

• PECARN febrile infant
• Kuppermann 2019
• febrile infant 60 days
• PECARN SBI rule
• febrile infant procalcitonin
• PECARN ANC urinalysis PCT
• Kuppermann Dayan Levine
• serious bacterial infection infant rule

Try

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

/api/calc/pecarn_febrile?age_days=36&negative_urinalysis=true&anc_per_ul=3000&pct_ng_ml=0.5

Full URL: https://api.magentlab.com/api/calc/pecarn_febrile?age_days=36&negative_urinalysis=true&anc_per_ul=3000&pct_ng_ml=0.5

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_febrile?age_days=36&negative_urinalysis=true&anc_per_ul=3000&pct_ng_ml=0.5"

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_febrile 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_days": "36",
      "anc_per_ul": "3000",
      "negative_urinalysis": "true",
      "pct_ng_ml": "0.5"
    },
    {
      "age_days": "36",
      "anc_per_ul": "3000",
      "negative_urinalysis": "true",
      "pct_ng_ml": "0.5"
    }
  ]
}

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_febrile",
  "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, Dayan PS, Levine DA, et al.",
        "doi": "10.1001/jamapediatrics.2018.5501",
        "id": "kuppermann-2019",
        "pmid": "30776077",
        "source": "JAMA Pediatr. 2019;173(4):342-351",
        "title": "A Clinical Prediction Rule to Identify Febrile Infants 60 Days and Younger at Low Risk for Serious Bacterial Infections."
      },
      "formula": "pecarn_febrile",
      "formula_expression": "low_risk iff negative_urinalysis and anc_per_ul <= 4090 and pct_ng_ml <= 1.71; age_days 0-60 pins the published population and is not a tree variable (Kuppermann 2019)",
      "anc_per_ul": 3.0e3,
      "criteria": [
        {
          "factor": "negative_urinalysis",
          "met": true
        },
        {
          "value": 3.0e3,
          "factor": "anc_le_4090",
          "met": true
        },
        {
          "value": 0.5,
          "factor": "pct_le_1_71",
          "met": true
        }
      ],
      "low_risk": true,
      "age_days": 36,
      "pct_ng_ml": 0.5
    },
    {
      "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, Dayan PS, Levine DA, et al.",
        "doi": "10.1001/jamapediatrics.2018.5501",
        "id": "kuppermann-2019",
        "pmid": "30776077",
        "source": "JAMA Pediatr. 2019;173(4):342-351",
        "title": "A Clinical Prediction Rule to Identify Febrile Infants 60 Days and Younger at Low Risk for Serious Bacterial Infections."
      },
      "formula": "pecarn_febrile",
      "formula_expression": "low_risk iff negative_urinalysis and anc_per_ul <= 4090 and pct_ng_ml <= 1.71; age_days 0-60 pins the published population and is not a tree variable (Kuppermann 2019)",
      "anc_per_ul": 3.0e3,
      "criteria": [
        {
          "factor": "negative_urinalysis",
          "met": true
        },
        {
          "value": 3.0e3,
          "factor": "anc_le_4090",
          "met": true
        },
        {
          "value": 0.5,
          "factor": "pct_le_1_71",
          "met": true
        }
      ],
      "low_risk": true,
      "age_days": 36,
      "pct_ng_ml": 0.5
    }
  ]
}

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, Dayan PS, Levine DA, et al.",
    "doi": "10.1001/jamapediatrics.2018.5501",
    "id": "kuppermann-2019",
    "pmid": "30776077",
    "source": "JAMA Pediatr. 2019;173(4):342-351",
    "title": "A Clinical Prediction Rule to Identify Febrile Infants 60 Days and Younger at Low Risk for Serious Bacterial Infections."
  },
  "formula": "pecarn_febrile",
  "formula_expression": "low_risk iff negative_urinalysis and anc_per_ul <= 4090 and pct_ng_ml <= 1.71; age_days 0-60 pins the published population and is not a tree variable (Kuppermann 2019)",
  "anc_per_ul": 3.0e3,
  "criteria": [
    {
      "factor": "negative_urinalysis",
      "met": true
    },
    {
      "value": 3.0e3,
      "factor": "anc_le_4090",
      "met": true
    },
    {
      "value": 0.5,
      "factor": "pct_le_1_71",
      "met": true
    }
  ],
  "low_risk": true,
  "age_days": 36,
  "pct_ng_ml": 0.5
}

Client errors (HTTP 400)

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

Related tools

• Rochester criteria — Apply the Dagan 1985 Rochester criteria and return low_risk only when every published criterion holds for an infant younger than 3 months.
• BRUE — Apply the Tieder 2016 AAP BRUE definition and return feature_count (0-4) and whether the published definition box holds (brue).

Payment

Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, 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

• HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged. HTTP 402 never includes the tool JSON.
• exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. 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.