# SCARF score

SCARF

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

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

## What it computes

Sum the four Hardin 2019 Sequential Clinical Assessment of Respiratory Function (SCARF) flags and return the integer total 0-4 plus whether the score is greater than the paper's proposed threshold of 2.

## When to use

When an agent already has caller-assigned Hardin 2019 SCARF flags for a single snapshot (admission or daily value) after rib fracture and needs the published 0-4 total and score-greater-than-2 flag without inventing named risk classes, serial day-1 versus day-2 inputs, or an analgesia or SSRF order.

## When not to use

- Not a medical device.
- Not an analgesia, epidural, or surgical stabilization of rib fractures (SSRF) order.
- magent does not measure incentive spirometry, count respiratory rate, score pain, or examine the chest. The caller assigns the four Hardin 2019 flags (incentive spirometry <50% predicted, respiratory rate >20 breaths/min, numeric pain score ≥5, and inadequate cough unable to clear secretions).
- This is a single snapshot (admission or daily value the caller supplies). It does not require serial day-1 versus day-2 inputs.
- Hardin 2019 proposed a threshold of score greater than 2. magent does not invent 0 = low / 1–2 = intermediate / 3–4 = high classes.

## Formula

```
SCARF = incentive_spirometry_lt_50_predicted + respiratory_rate_gt_20 + pain_score_ge_5 + inadequate_cough; each 1; Hardin 2019; max 4; proposed threshold score > 2 (scarf_gt_2); caller-assigned flags; magent does not measure spirometry or examine the chest
```

## Citation

[The Sequential Clinical Assessment of Respiratory Function (SCARF) score: A dynamic pulmonary physiologic score that predicts adverse outcomes in critically ill rib fracture patients](https://doi.org/10.1097/TA.0000000000002480)
Hardin KS, Leasia KN, Haenel J, Moore EE, Burlew CC, Pieracci FM
J Trauma Acute Care Surg. 2019;87(6):1260-1268
DOI: [10.1097/TA.0000000000002480](https://doi.org/10.1097/TA.0000000000002480)

## Worked example

### All flags false

Given: `inadequate_cough=false, incentive_spirometry_lt_50_predicted=false, pain_score_ge_5=false, respiratory_rate_gt_20=false`

1. incentive_spirometry_lt_50_predicted, respiratory_rate_gt_20, pain_score_ge_5, and inadequate_cough are false
2. score = 0 (max 4); scarf_gt_2 false


### Three flags (published score > 2 threshold)

Given: `inadequate_cough=false, incentive_spirometry_lt_50_predicted=true, pain_score_ge_5=true, respiratory_rate_gt_20=true`

1. Three Hardin 2019 flags true, 1 point each
2. score = 3 (max 4); scarf_gt_2 true because 3 > 2


### All flags true

Given: `inadequate_cough=true, incentive_spirometry_lt_50_predicted=true, pain_score_ge_5=true, respiratory_rate_gt_20=true`

1. All four Hardin 2019 flags true, 1 point each
2. score = 4 (max 4); scarf_gt_2 true


## Also searched as

- SCARF score
- Sequential Clinical Assessment of Respiratory Function
- Hardin SCARF
- rib fracture SCARF
- Hardin 2019 respiratory score
- incentive spirometry rib fracture score
- inadequate cough rib score

## Parameters

- `incentive_spirometry_lt_50_predicted` (boolean, required): Incentive spirometry volume <50% of predicted as assigned by the caller (Hardin 2019). true or false. magent does not measure incentive spirometry.
- `respiratory_rate_gt_20` (boolean, required): Respiratory rate >20 breaths/min as assigned by the caller (Hardin 2019). true or false. magent does not count respiratory rate.
- `pain_score_ge_5` (boolean, required): Numeric pain score ≥5 as assigned by the caller (Hardin 2019). true or false. magent does not score pain.
- `inadequate_cough` (boolean, required): Inadequate cough (unable to clear secretions) as assigned by the caller (Hardin 2019). true or false. magent does not examine the chest or cough.

## 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/scarf`
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": [
    {
      "inadequate_cough": "false",
      "incentive_spirometry_lt_50_predicted": "false",
      "pain_score_ge_5": "false",
      "respiratory_rate_gt_20": "false"
    },
    {
      "inadequate_cough": "false",
      "incentive_spirometry_lt_50_predicted": "false",
      "pain_score_ge_5": "false",
      "respiratory_rate_gt_20": "false"
    }
  ]
}
```

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

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/scarf",
  "items": [
    {
      "components": [
        {
          "factor": "incentive_spirometry_lt_50_predicted",
          "points": 0,
          "present": false
        },
        {
          "factor": "respiratory_rate_gt_20",
          "points": 0,
          "present": false
        },
        {
          "factor": "pain_score_ge_5",
          "points": 0,
          "present": false
        },
        {
          "factor": "inadequate_cough",
          "points": 0,
          "present": false
        }
      ],
      "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": "Hardin KS, Leasia KN, Haenel J, Moore EE, Burlew CC, Pieracci FM",
        "doi": "10.1097/TA.0000000000002480",
        "id": "hardin-2019",
        "pmid": "31425473",
        "source": "J Trauma Acute Care Surg. 2019;87(6):1260-1268",
        "title": "The Sequential Clinical Assessment of Respiratory Function (SCARF) score: A dynamic pulmonary physiologic score that predicts adverse outcomes in critically ill rib fracture patients"
      },
      "formula": "scarf",
      "formula_expression": "SCARF = incentive_spirometry_lt_50_predicted + respiratory_rate_gt_20 + pain_score_ge_5 + inadequate_cough; each 1; Hardin 2019; max 4; proposed threshold score > 2 (scarf_gt_2); caller-assigned flags; magent does not measure spirometry or examine the chest",
      "max_score": 4,
      "score": 0,
      "scarf_gt_2": false
    },
    {
      "components": [
        {
          "factor": "incentive_spirometry_lt_50_predicted",
          "points": 0,
          "present": false
        },
        {
          "factor": "respiratory_rate_gt_20",
          "points": 0,
          "present": false
        },
        {
          "factor": "pain_score_ge_5",
          "points": 0,
          "present": false
        },
        {
          "factor": "inadequate_cough",
          "points": 0,
          "present": false
        }
      ],
      "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": "Hardin KS, Leasia KN, Haenel J, Moore EE, Burlew CC, Pieracci FM",
        "doi": "10.1097/TA.0000000000002480",
        "id": "hardin-2019",
        "pmid": "31425473",
        "source": "J Trauma Acute Care Surg. 2019;87(6):1260-1268",
        "title": "The Sequential Clinical Assessment of Respiratory Function (SCARF) score: A dynamic pulmonary physiologic score that predicts adverse outcomes in critically ill rib fracture patients"
      },
      "formula": "scarf",
      "formula_expression": "SCARF = incentive_spirometry_lt_50_predicted + respiratory_rate_gt_20 + pain_score_ge_5 + inadequate_cough; each 1; Hardin 2019; max 4; proposed threshold score > 2 (scarf_gt_2); caller-assigned flags; magent does not measure spirometry or examine the chest",
      "max_score": 4,
      "score": 0,
      "scarf_gt_2": false
    }
  ]
}
```

## Response fields

- `formula` (string): scarf
- `formula_expression` (string): Exact expression used
- `score` (integer): SCARF points 0-4
- `max_score` (integer): Always 4
- `scarf_gt_2` (boolean): true iff score > 2 (Hardin 2019 proposed threshold). Not a named risk class and not an analgesia or SSRF order.
- `components` (array): Per-flag Hardin 2019 points
- `citation` (object): Hardin 2019 J Trauma Acute Care Surg citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "components": [
    {
      "factor": "incentive_spirometry_lt_50_predicted",
      "points": 0,
      "present": false
    },
    {
      "factor": "respiratory_rate_gt_20",
      "points": 0,
      "present": false
    },
    {
      "factor": "pain_score_ge_5",
      "points": 0,
      "present": false
    },
    {
      "factor": "inadequate_cough",
      "points": 0,
      "present": false
    }
  ],
  "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": "Hardin KS, Leasia KN, Haenel J, Moore EE, Burlew CC, Pieracci FM",
    "doi": "10.1097/TA.0000000000002480",
    "id": "hardin-2019",
    "pmid": "31425473",
    "source": "J Trauma Acute Care Surg. 2019;87(6):1260-1268",
    "title": "The Sequential Clinical Assessment of Respiratory Function (SCARF) score: A dynamic pulmonary physiologic score that predicts adverse outcomes in critically ill rib fracture patients"
  },
  "formula": "scarf",
  "formula_expression": "SCARF = incentive_spirometry_lt_50_predicted + respiratory_rate_gt_20 + pain_score_ge_5 + inadequate_cough; each 1; Hardin 2019; max 4; proposed threshold score > 2 (scarf_gt_2); caller-assigned flags; magent does not measure spirometry or examine the chest",
  "max_score": 4,
  "score": 0,
  "scarf_gt_2": false
}
```

## Errors

- HTTP 400 `invalid_scarf`: SCARF needs Hardin 2019 incentive-spirometry, respiratory-rate, pain, and cough flags. 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

- [RibScore](https://magentlab.com/docs/ribscore) — Sum the six Chapman 2016 RibScore radiographic flags and return the integer total 0-6. That paper associated the score linearly with pneumonia, respiratory failure, and tracheostomy.
- [STUMBL](https://magentlab.com/docs/stumbl) — Sum Battle 2014 Table 4 STUMBL points from caller-assigned age, rib fracture count, chronic lung disease, preinjury anticoagulants, and SpO2, and return the Table 5 complication-probability band.

## 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.