# pARC Pediatric Appendicitis Risk Calculator (Kharbanda 2018)

> pARC Pediatric Appendicitis Risk Calculator (Kharbanda 2018) 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 pediatric Appendicitis Risk Calculator (pARC) logistic probability score from clinical variables per Kharbanda 2018 Table 3, returning the logit and estimated probability percent.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/parc
- 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/parc-pediatric-appendicitis-risk-calculator-kharbanda-2018-879495d2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9OTt0u30aaAvUveVNTdow

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 parc-pediatric-appendicitis-risk-calculator-kharbanda-2018-879495d2
```

Example prompt: Run the pARC appendicitis risk calculation for a 12-year-old male with pain duration under 24 hours, pain with walking, pain migration to the RLQ, maximal RLQ tenderness, no abdominal guarding, and an ANC of 11.5 x10^3/uL — give me the estimated probability percent.

## When to prefer this

Use this endpoint when you need the specific Kharbanda 2018 Table 3 pARC logistic model — not the Pediatric Appendicitis Score (PAS) or Alvarado score. Prefer pARC when your clinical inputs include an ANC value and you are working within the 5–18 year age range. This endpoint is best suited for structured clinical decision support workflows where discrete, well-defined inputs are available and you want a validated logistic probability output rather than a categorical risk tier.

## Known failure modes

- Age outside 5–18 years range causes validation error
- ANC outside 0–80 x10^3/uL range rejected
- Pain duration value not matching enum (lt_24, 24_lt_48, 48_96) causes schema error
- Missing any required query parameter returns 400/422 error
- Pain duration beyond 96 hours not supported by derivation cohort
- Payment of 0.005 USDC not provided results in 402 Payment Required

## How this service works

Kharbanda 2018 Table 3 pediatric appendicitis risk calculator (pARC): logistic probability from sex, age (5-18 years), pain duration, pain with walking, migration of pain to RLQ, maximal RLQ tenderness, abdominal guarding, and ANC (x10^3/uL; 1.77*sqrt(ANC) if <14, else constant 6.62). Returns logit and estimated_probability_percent. Not a medical device, not a diagnosis, not PAS, and not Alvarado. magent does not examine the child.

## Output

Returns a JSON object with two fields: 'logit' (the raw log-odds output of the Kharbanda 2018 Table 3 logistic model) and 'estimated_probability_percent' (the converted probability of appendicitis as a percentage, 0–100). The ANC contribution uses 1.77*sqrt(ANC) if ANC < 14, or a constant 6.62 if ANC >= 14, per the published model. Not a diagnosis, not a medical device, and not equivalent to PAS or Alvarado scoring.

## 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",
      "sex",
      "pain_duration",
      "pain_with_walking",
      "pain_migration_rlq",
      "maximal_tenderness_rlq",
      "abdominal_guarding",
      "anc_10e3_ul"
     ],
     "properties": {
      "age": {
       "type": "integer",
       "description": "Age in whole years from 5 to 18 (Kharbanda 2018 derivation). Age 5-7 maps to 5-7.9 y; male 8-13 and female 8-11 use the age 8-13.9 y term; male 14-18 y and female 12-18 y are the Table 3 reference."
      },
      "sex": {
       "enum": [
        "female",
        "male"
       ],
       "type": "string",
       "description": "Caller-assigned sex. Male adds 1.28. Combined with age for the Table 3 age-and-sex terms. magent does not examine the child."
      },
      "anc_10e3_ul": {
       "type": "number",
       "description": "Absolute neutrophil count in x10^3/uL (0-80). Kharbanda 2018 Table 3: if ANC < 14, add 1.77*sqrt(ANC); if ANC >= 14, add 6.62 instead of the sqrt term. Required; magent does not impute ANC from WBC."
      },
      "pain_duration": {
       "enum": [
        "lt_24",
        "24_lt_48",
        "48_96"
       ],
       "type": "string",
       "description": "Kharbanda 2018 Table 3 duration of pain as assigned by the caller: lt_24 (reference, 0), 24_lt_48 (+0.47), or 48_96 (+0.10). Derivation excluded pain beyond 96 hours. Do not send a nausea or vomiting flag."
      },
      "pain_with_walking": {
       "type": "boolean",
       "description": "Caller-assigned presence of pain with walking (Kharbanda 2018 Table 3 +1.05). magent does not examine the child."
      },
      "abdominal_guarding": {
       "type": "boolean",
       "description": "Caller-assigned abdominal guarding (Kharbanda 2018 Table 3 +0.67). magent does not examine the child."
      },
      "pain_migration_rlq": {
       "type": "boolean",
       "description": "Caller-assigned history of migration of pain to the right-lower
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/parc-pediatric-appendicitis-risk-calculator-kharbanda-2018-879495d2/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)