# Palchak 2003 Pediatric Head CT Decision Rule (magent)

> Palchak 2003 Pediatric Head CT Decision Rule (magent) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-13).

Calculates pediatric head CT necessity risk (high vs. low) using the Palchak 2003 rule for children aged 0–17 after blunt head trauma

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/palchak
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/palchak-2003-pediatric-head-ct-decision-rule-magent-2600d94e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rd_8aJj4dE4mkpmUu5F-L

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 palchak-2003-pediatric-head-ct-decision-rule-magent-2600d94e
```

Example prompt: Run the Palchak 2003 head CT risk rule for a 2-year-old who has abnormal mental status, a scalp hematoma, and a history of vomiting after a fall — no clinical signs of skull fracture and no headache reported.

## When to prefer this

Use this endpoint when you need a structured, programmatic implementation of the Palchak 2003 pediatric head CT clinical decision rule specifically — not PECARN, CATCH, CHALICE, Canadian CT Head, or NEXUS. It is appropriate for ages 0–17 after blunt head trauma and correctly applies the age-gated scalp hematoma scoring. Prefer this over manual rule lookup when you need machine-readable risk output in an automated clinical decision support workflow.

## Known failure modes

- Age 18 or above is rejected — the rule only covers ages 0–17
- Missing required query parameters (age, abnormal_mental_status, clinical_signs_skull_fracture, history_of_vomiting, scalp_hematoma, headache) returns an error
- Non-boolean values for boolean fields are rejected
- Non-integer or out-of-range age values return a validation error
- Payment failure (insufficient USDC balance or x402 protocol issue) returns a 402 response

## How this service works

Palchak 2003. High risk after blunt head trauma in children 0-17 if any applicable predictor: abnormal mental status, clinical signs of skull fracture, history of vomiting, scalp hematoma (only if age <=2), or headache. Else low risk. ct_not_low_risk iff high. Scalp hematoma is parsed at all ages but scores only when age is 0, 1, or 2. Not PECARN, CATCH, CHALICE, Canadian CT Head, or NEXUS. magent does not examine the child or order CT. Not a diagnosis or medical device.

## Output

Returns a risk classification (high or low risk) and a ct_not_low_risk boolean flag indicating whether the patient is NOT low risk (i.e., whether a CT scan may be warranted), based on presence or absence of the Palchak 2003 predictors. Scalp hematoma only counts as a high-risk predictor for ages 0–2.

## 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",
      "abnormal_mental_status",
      "clinical_signs_skull_fracture",
      "history_of_vomiting",
      "scalp_hematoma",
      "headache"
     ],
     "properties": {
      "age": {
       "type": "integer",
       "description": "Age in years (integer 0-17). Scalp hematoma is a high-risk predictor only when age is 0, 1, or 2; age 3-17 parse scalp_hematoma but do not score it. Age 18 is rejected."
      },
      "headache": {
       "type": "boolean",
       "description": "Headache as assigned by the caller. true or false. High-risk at all ages 0-17 (Palchak 2003 listed headache as a predictor). magent does not examine the child."
      },
      "scalp_hematoma": {
       "type": "boolean",
       "description": "Scalp hematoma as assigned by the caller. true or false. High-risk only when age is 0, 1, or 2; parsed but not scored when age >= 3. magent does not examine the scalp."
      },
      "history_of_vomiting": {
       "type": "boolean",
       "description": "History of vomiting as assigned by the caller. true or false. High-risk at all ages 0-17."
      },
      "abnormal_mental_status": {
       "type": "boolean",
       "description": "Abnormal mental status as assigned by the caller. true or false. High-risk at all ages 0-17. magent does not examine the child or assign GCS."
      },
      "clinical_signs_skull_fracture": {
       "type": "boolean",
       "description": "Clinical signs of skull fracture as assigned by the caller. true or false. High-risk at all ages 0-17. magent does not examine the child or read a radiograph."
      }
     }
    }
   },
   "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/palchak-2003-pediatric-head-ct-decision-rule-magent-2600d94e/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)