# PedSRC blunt abdomen

PedSRC blunt abdomen

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/pedsrc`
HTML: https://magentlab.com/docs/pedsrc
Markdown: https://magentlab.com/docs/pedsrc.md

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

## What it computes

Apply the Streck 2017 Pediatric Surgery Research Collaborative five-variable prediction rule and return whether the child is at very low risk of blunt intra-abdominal injury (none of five caller-assigned findings present). Does not order a CT.

## When to use

When an agent has caller-assigned findings after blunt abdominal trauma in a child and needs the Streck 2017 PedSRC rule, not Holmes 2013 PECARN IAI (pecarn-iai).

## When not to use

- Not a medical device. Not a diagnosis. magent does not examine the child.
- This tool is the Streck 2017 five-variable PedSRC prediction rule only. It is not Holmes 2013 PECARN IAI (pecarn-iai). Presence of a criterion does not mandate CT. Do not order a CT from this tool.
- AST is a positive variable iff greater than 200 U/L (200 is not positive). magent does not assay AST, amylase, or lipase; the caller assigns abnormal_pancreatic_enzymes.
- magent does not take age. The published derivation was age <16 years. The five clinical variables determine very_low_risk.

## Formula

```
very_low_risk iff no ast_gt_200 and no abnormal_abdominal_exam and no abnormal_chest_xray and no abdominal_pain and no abnormal_pancreatic_enzymes
```

## Citation

[Identifying Children at Very Low Risk for Blunt Intra-Abdominal Injury in Whom CT of the Abdomen Can Be Avoided Safely](https://doi.org/10.1016/j.jamcollsurg.2016.12.041)
Streck CJ, Blakely ML, Huang EY, Vogel AM, Santore MT, Tsao K, Falcone RA, Dassinger MS, Haynes JH, Russell RT, Naik-Mathuria BJ, St Peter SD, Mooney DP, Upperman JS; Pediatric Surgery Research Collaborative
J Am Coll Surg. 2017;224(4):449-458.e3
DOI: [10.1016/j.jamcollsurg.2016.12.041](https://doi.org/10.1016/j.jamcollsurg.2016.12.041)

## Worked example

### AST 80 U/L and all four flags absent

Given: `abdominal_pain=false, abnormal_abdominal_exam=false, abnormal_chest_xray=false, abnormal_pancreatic_enzymes=false, ast_u_l=80`

1. AST 80 is not >200 U/L; no abnormal abdominal examination, abnormal chest x-ray, abdominal pain, or abnormal pancreatic enzymes
2. very_low_risk is true; this tool does not order a CT


### AST greater than 200 U/L alone is not very low risk

Given: `abdominal_pain=false, abnormal_abdominal_exam=false, abnormal_chest_xray=false, abnormal_pancreatic_enzymes=false, ast_u_l=201`

1. AST 201 is >200 U/L; the four flags remain absent
2. very_low_risk is false. Presence of this criterion does not mandate CT


## Also searched as

- PedSRC
- Streck 2017
- pediatric blunt abdominal trauma
- very low risk intra-abdominal injury
- PedSRC abdominal CT rule
- Pediatric Surgery Research Collaborative
- blunt IAI children
- Streck abdominal injury prediction

## Parameters

- `ast_u_l` (number, required): Aspartate aminotransferase in U/L (number 1-10000). Positive Streck 2017 variable iff >200 U/L (200 is not positive). magent does not assay AST.
- `abnormal_abdominal_exam` (boolean, required): Abnormal abdominal examination (wall trauma, distension, or tenderness) as assigned by the caller. true means the finding is present and very_low_risk is false. true or false. magent does not examine the child.
- `abnormal_chest_xray` (boolean, required): Abnormal chest x-ray as assigned by the caller. true means the finding is present and very_low_risk is false. true or false. magent does not read a radiograph.
- `abdominal_pain` (boolean, required): Reported abdominal pain as assigned by the caller. true means pain is present and very_low_risk is false. true or false. magent does not take a pain score.
- `abnormal_pancreatic_enzymes` (boolean, required): Abnormal amylase or lipase as assigned by the caller. true means the finding is present and very_low_risk is false. true or false. magent does not assay amylase or lipase.

## 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.

Method: `POST /api/calc/pedsrc`
Max items: 25
Price: unit_amount + extra_item_amount * (n - 1) (unit 5000 atomic, extra 2000 atomic)
Status: 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:

```json
{
  "items": [
    {
      "abdominal_pain": "false",
      "abnormal_abdominal_exam": "false",
      "abnormal_chest_xray": "false",
      "abnormal_pancreatic_enzymes": "false",
      "ast_u_l": "80"
    },
    {
      "abdominal_pain": "false",
      "abnormal_abdominal_exam": "false",
      "abnormal_chest_xray": "false",
      "abnormal_pancreatic_enzymes": "false",
      "ast_u_l": "80"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/pedsrc

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/pedsrc",
  "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": "Streck CJ, Blakely ML, Huang EY, Vogel AM, Santore MT, Tsao K, Falcone RA, Dassinger MS, Haynes JH, Russell RT, Naik-Mathuria BJ, St Peter SD, Mooney DP, Upperman JS; Pediatric Surgery Research Collaborative",
        "doi": "10.1016/j.jamcollsurg.2016.12.041",
        "id": "streck-2017",
        "pmid": "28130170",
        "source": "J Am Coll Surg. 2017;224(4):449-458.e3",
        "title": "Identifying Children at Very Low Risk for Blunt Intra-Abdominal Injury in Whom CT of the Abdomen Can Be Avoided Safely"
      },
      "formula": "pedsrc",
      "formula_expression": "very_low_risk iff no ast_gt_200 and no abnormal_abdominal_exam and no abnormal_chest_xray and no abdominal_pain and no abnormal_pancreatic_enzymes",
      "ast_u_l": 80.0,
      "criteria": [
        {
          "value": 80.0,
          "factor": "no_ast_gt_200",
          "met": true
        },
        {
          "factor": "no_abnormal_abdominal_exam",
          "met": true
        },
        {
          "factor": "no_abnormal_chest_xray",
          "met": true
        },
        {
          "factor": "no_abdominal_pain",
          "met": true
        },
        {
          "factor": "no_abnormal_pancreatic_enzymes",
          "met": true
        }
      ],
      "very_low_risk": true
    },
    {
      "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": "Streck CJ, Blakely ML, Huang EY, Vogel AM, Santore MT, Tsao K, Falcone RA, Dassinger MS, Haynes JH, Russell RT, Naik-Mathuria BJ, St Peter SD, Mooney DP, Upperman JS; Pediatric Surgery Research Collaborative",
        "doi": "10.1016/j.jamcollsurg.2016.12.041",
        "id": "streck-2017",
        "pmid": "28130170",
        "source": "J Am Coll Surg. 2017;224(4):449-458.e3",
        "title": "Identifying Children at Very Low Risk for Blunt Intra-Abdominal Injury in Whom CT of the Abdomen Can Be Avoided Safely"
      },
      "formula": "pedsrc",
      "formula_expression": "very_low_risk iff no ast_gt_200 and no abnormal_abdominal_exam and no abnormal_chest_xray and no abdominal_pain and no abnormal_pancreatic_enzymes",
      "ast_u_l": 80.0,
      "criteria": [
        {
          "value": 80.0,
          "factor": "no_ast_gt_200",
          "met": true
        },
        {
          "factor": "no_abnormal_abdominal_exam",
          "met": true
        },
        {
          "factor": "no_abnormal_chest_xray",
          "met": true
        },
        {
          "factor": "no_abdominal_pain",
          "met": true
        },
        {
          "factor": "no_abnormal_pancreatic_enzymes",
          "met": true
        }
      ],
      "very_low_risk": true
    }
  ]
}
```

## Response fields

- `formula` (string): pedsrc
- `formula_expression` (string): Streck 2017 five-variable very-low-risk prediction rule
- `very_low_risk` (boolean): true only when none of the five caller-assigned findings is present. Does not order a CT. Presence of a criterion does not mandate CT. Not a diagnosis.
- `ast_u_l` (number): AST in U/L used for the >200 U/L Streck 2017 variable
- `criteria` (array): Per-factor rows with factor and met; met is true when that Streck 2017 finding is absent (no_ast_gt_200, no_abnormal_abdominal_exam, no_abnormal_chest_xray, no_abdominal_pain, no_abnormal_pancreatic_enzymes)
- `citation` (object): Streck 2017 J Am Coll Surg citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "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": "Streck CJ, Blakely ML, Huang EY, Vogel AM, Santore MT, Tsao K, Falcone RA, Dassinger MS, Haynes JH, Russell RT, Naik-Mathuria BJ, St Peter SD, Mooney DP, Upperman JS; Pediatric Surgery Research Collaborative",
    "doi": "10.1016/j.jamcollsurg.2016.12.041",
    "id": "streck-2017",
    "pmid": "28130170",
    "source": "J Am Coll Surg. 2017;224(4):449-458.e3",
    "title": "Identifying Children at Very Low Risk for Blunt Intra-Abdominal Injury in Whom CT of the Abdomen Can Be Avoided Safely"
  },
  "formula": "pedsrc",
  "formula_expression": "very_low_risk iff no ast_gt_200 and no abnormal_abdominal_exam and no abnormal_chest_xray and no abdominal_pain and no abnormal_pancreatic_enzymes",
  "ast_u_l": 80.0,
  "criteria": [
    {
      "value": 80.0,
      "factor": "no_ast_gt_200",
      "met": true
    },
    {
      "factor": "no_abnormal_abdominal_exam",
      "met": true
    },
    {
      "factor": "no_abnormal_chest_xray",
      "met": true
    },
    {
      "factor": "no_abdominal_pain",
      "met": true
    },
    {
      "factor": "no_abnormal_pancreatic_enzymes",
      "met": true
    }
  ],
  "very_low_risk": true
}
```

## Errors

- HTTP 400 `invalid_ast`: ast_u_l must be a number from 1 to 10000 Returned before settlement; you are not charged.
- HTTP 400 `invalid_flag`: boolean clinical flags must be true or false Returned before settlement; you are not charged.
- HTTP 400 `invalid_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
- HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
- HTTP 400 `invalid_item`: each items entry must be a JSON object Returned before settlement; you are not charged.

Shared HTTP 402 and 503: https://magentlab.com/docs/payments

## Related tools

- [PECARN pediatric IAI](https://magentlab.com/docs/pecarn-iai) — Apply the Holmes 2013 PECARN seven-variable prediction rule and return whether the child is at very low risk of intra-abdominal injury requiring acute intervention (all seven caller-assigned findings absent). Does not order a CT.
- [SIPA](https://magentlab.com/docs/sipa) — Compute Acker 2015 SIPA as heart rate in bpm divided by cuff systolic pressure in mm Hg, then compare the ratio with the published age-band cutoff.
- [PECARN pediatric head CT](https://magentlab.com/docs/pecarn-head) — 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.

## 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.

- GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall).
- HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote.
- Sign accepts[0] (exact, EIP-3009) with validBefore = now + maxTimeoutSeconds (600 seconds), or accepts[1] (batch-settlement deposit/voucher) on product GET. Ping and POST {items} stay exact. Magent retries transient facilitator 429/5xx before answering.
- Retry the same URL with PAYMENT-SIGNATURE (base64 JSON of accepted and payload). Magent attaches canonical extensions.bazaar on CDP verify/settle; echoing 402 bazaar is optional.
- Success is HTTP 200 JSON plus PAYMENT-RESPONSE. exact settles before the tool. batch-settlement verifies (and deposit-settles) before the tool and commits the charge after HTTP 2xx. HTTP 503: retry the same PAYMENT-SIGNATURE. Mint a new exact nonce only after a new HTTP 402.

- offered `exact` on eip155:8453: Fixed-price USDC on Base. The buyer authorizes the advertised amount (EIP-3009). magent settles before the tool runs (paymentFlow upfront). extra.assetTransferMethod=eip3009 extra.paymentFlow=upfront.
- offered `batch-settlement` on eip155:8453: Payment-channel vouchers claimed later in batches. Exact stays accepts[0]. Same-path POST {items} is still exact. extra.assetTransferMethod=eip3009 extra.paymentFlow=authorization.

- not offered `upto`: Not offered. Usage-based: buyer authorizes a ceiling, seller settles the actual amount after work. Reserved for a future metered tool. Not for current calculators or code search.

Same-path POST {items} is still scheme exact: one EIP-3009 authorization for GET unit plus $0.002 per extra item. That is not x402 batch-settlement (payment channels / vouchers).

Shared HTTP 402 and 503 table: https://magentlab.com/docs/payments

Stdio MCP (one process per host): https://magentlab.com/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.