# PECARN Febrile Infant Low-Risk Rule (Kuppermann 2019)

> PECARN Febrile Infant Low-Risk Rule (Kuppermann 2019) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Applies the Kuppermann 2019 PECARN prediction rule to classify febrile infants ≤60 days old as low-risk or not, based on urinalysis, ANC, and procalcitonin values.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/pecarn_febrile
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pecarn-febrile-infant-low-risk-rule-kuppermann-2019-bac95220
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6JbAln_JREl26_PnKd37R

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 pecarn-febrile-infant-low-risk-rule-kuppermann-2019-bac95220
```

Example prompt: Run the Kuppermann 2019 PECARN febrile infant rule for a 32-day-old: the urinalysis is negative, ANC is 3800 cells/µL, and procalcitonin is 1.2 ng/mL — is this infant low-risk?

## When to prefer this

Use this endpoint specifically when you need to apply the Kuppermann 2019 PECARN three-variable febrile infant rule (negative UA + ANC ≤4090 + PCT ≤1.71) to infants 0-60 days old. Prefer this over other febrile infant rules (Rochester, Boston, Philadelphia, Step-by-Step) when the clinical workflow uses procalcitonin alongside ANC and UA. Do not use for infants older than 60 days, for head injury PECARN, or when laboratory values have not yet been obtained.

## Known failure modes

- age_days outside 0-60 range returns validation error
- pct_ng_ml outside 0.01-100 range returns validation error
- anc_per_ul outside 0-100000 returns validation error
- missing required query parameters returns 400-level error
- payment failure via x402 protocol returns 402 Payment Required

## How this service works

Kuppermann 2019 PECARN prediction rule for febrile infants 60 days and younger. Low-risk only if all three hold: caller-assigned negative urinalysis, ANC 4090/uL or less, and serum procalcitonin 1.71 ng/mL or less. Age 0-60 pins the published population and is not a tree variable. Returns low_risk. magent does not assay UA, ANC, or PCT. Not Rochester, Boston, Philadelphia, Step-by-Step, later AAP/PECARN cutoffs, or pecarn-head. Not a medical device and not a discharge or LP order.

## Output

Returns a low_risk indicator (true or false) based on whether all three Kuppermann 2019 PECARN criteria are simultaneously met: caller-assigned negative urinalysis, ANC ≤4090 cells/µL, and procalcitonin ≤1.71 ng/mL. Does not perform laboratory assays; it only applies the decision rule to caller-provided values.

## 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_days",
      "negative_urinalysis",
      "anc_per_ul",
      "pct_ng_ml"
     ],
     "properties": {
      "age_days": {
       "type": "integer",
       "description": "Chronological age in days (integer 0-60). Kuppermann 2019 studied febrile infants 60 days and younger. Age pins the published population and is not a tree variable; age 0 and age 60 can both be low-risk when the three laboratory criteria hold."
      },
      "pct_ng_ml": {
       "type": "number",
       "description": "Serum procalcitonin in ng/mL. Range 0.01-100. Low-risk requires 1.71 ng/mL or less (1.71 meets; 1.72 does not). magent does not assay procalcitonin."
      },
      "anc_per_ul": {
       "type": "number",
       "description": "Absolute neutrophil count in cells/µL. Range 0-100000. Low-risk requires ANC 4090/µL or less (4090 meets; 4091 does not). magent does not assay ANC."
      },
      "negative_urinalysis": {
       "type": "boolean",
       "description": "Caller-assigned negative urinalysis as used in Kuppermann 2019. true means the UA is negative. true or false. magent does not assay UA."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pecarn-febrile-infant-low-risk-rule-kuppermann-2019-bac95220/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)