# SULF-FAST sulfa antibiotic allergy rule

SULF-FAST

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

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

## What it computes

Sum the three Waldron 2023 SULF-FAST flags for a reported trimethoprim-sulfamethoxazole allergy and return the 0–5 score, published risk group (low if score < 3, elevated if ≥ 3), and low_risk_for_testing (score < 3).

## When to use

When an agent has already assigned the three Waldron 2023 SULF-FAST flags for a patient who reports trimethoprim-sulfamethoxazole (sulfa antibiotic) allergy and needs the published point total and risk group. magent does not take an allergy history and does not diagnose allergy or issue a delabeling order. This is not PEN-FAST.

## When not to use

- Not a medical device.
- Not an allergy diagnosis and not a delabeling order.
- magent does not take an allergy history.
- Not PEN-FAST. Waldron 2023 adapted the PEN-FAST flags for reported trimethoprim-sulfamethoxazole (sulfa antibiotic) allergy.
- Waldron 2023 uses two risk groups (low if score < 3, elevated if score ≥ 3), not the Trubiano 2020 four-tier PEN-FAST groups.
- A score < 3 is the paper's low-risk cutoff and does not replace specialist testing when indicated.

## Formula

```
SULF-FAST = five_or_fewer_years_ago (true 2) + anaphylaxis_angioedema_or_scar (true 2) + treatment_required (true 1); Waldron 2023; max 5; score < 3 low, score ≥ 3 elevated; low_risk_for_testing iff score < 3
```

## Citation

[Development and Validation of a Sulfa Antibiotic Allergy Clinical Decision Rule](https://doi.org/10.1001/jamanetworkopen.2023.16776)
Waldron JL, Rose M, Vogrin S, Krantz MS, Bolotte R, Phillips EJ, Trubiano JA
JAMA Netw Open. 2023;6(6):e2316776
DOI: [10.1001/jamanetworkopen.2023.16776](https://doi.org/10.1001/jamanetworkopen.2023.16776)

## Worked example

### All three flags false

Given: `anaphylaxis_angioedema_or_scar=false, five_or_fewer_years_ago=false, treatment_required=false`

1. five_or_fewer_years_ago false → 0; anaphylaxis_angioedema_or_scar false → 0; treatment_required false → 0
2. Score = 0 (max 5); risk = low; low_risk_for_testing = true


### All three flags true

Given: `anaphylaxis_angioedema_or_scar=true, five_or_fewer_years_ago=true, treatment_required=true`

1. five_or_fewer_years_ago true → 2; anaphylaxis_angioedema_or_scar true → 2; treatment_required true → 1
2. Score = 5 (max 5); risk = elevated; low_risk_for_testing = false


## Also searched as

- SULF FAST
- sulfa allergy
- SULF-FAST
- Waldron 2023
- trimethoprim-sulfamethoxazole allergy
- TMP-SMX allergy
- sulfa antibiotic allergy
- SULFFAST

## Parameters

- `five_or_fewer_years_ago` (boolean, required): Allergy event 5 or fewer years ago as assigned by the caller (Waldron 2023). true scores 2. magent does not take an allergy history.
- `anaphylaxis_angioedema_or_scar` (boolean, required): Anaphylaxis/angioedema or potential SCAR as one 2-point criterion (Waldron 2023). true scores 2; do not add both phenotypes separately. magent does not take an allergy history.
- `treatment_required` (boolean, required): Treatment required for the allergy episode as assigned by the caller (Waldron 2023). true scores 1. magent does not take an allergy history.

## 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/sulf_fast`
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": [
    {
      "anaphylaxis_angioedema_or_scar": "false",
      "five_or_fewer_years_ago": "false",
      "treatment_required": "false"
    },
    {
      "anaphylaxis_angioedema_or_scar": "false",
      "five_or_fewer_years_ago": "false",
      "treatment_required": "false"
    }
  ]
}
```

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

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/sulf_fast",
  "items": [
    {
      "components": [
        {
          "factor": "five_or_fewer_years_ago",
          "points": 0,
          "present": false
        },
        {
          "factor": "anaphylaxis_angioedema_or_scar",
          "points": 0,
          "present": false
        },
        {
          "factor": "treatment_required",
          "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": "Waldron JL, Rose M, Vogrin S, Krantz MS, Bolotte R, Phillips EJ, Trubiano JA",
        "doi": "10.1001/jamanetworkopen.2023.16776",
        "id": "waldron-2023",
        "pmid": "37273210",
        "source": "JAMA Netw Open. 2023;6(6):e2316776",
        "title": "Development and Validation of a Sulfa Antibiotic Allergy Clinical Decision Rule"
      },
      "formula": "sulf_fast",
      "formula_expression": "SULF-FAST = five_or_fewer_years_ago (true 2) + anaphylaxis_angioedema_or_scar (true 2) + treatment_required (true 1); Waldron 2023; max 5; score < 3 low, score ≥ 3 elevated; low_risk_for_testing iff score < 3",
      "max_score": 5,
      "score": 0,
      "risk": "low",
      "low_risk_for_testing": true
    },
    {
      "components": [
        {
          "factor": "five_or_fewer_years_ago",
          "points": 0,
          "present": false
        },
        {
          "factor": "anaphylaxis_angioedema_or_scar",
          "points": 0,
          "present": false
        },
        {
          "factor": "treatment_required",
          "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": "Waldron JL, Rose M, Vogrin S, Krantz MS, Bolotte R, Phillips EJ, Trubiano JA",
        "doi": "10.1001/jamanetworkopen.2023.16776",
        "id": "waldron-2023",
        "pmid": "37273210",
        "source": "JAMA Netw Open. 2023;6(6):e2316776",
        "title": "Development and Validation of a Sulfa Antibiotic Allergy Clinical Decision Rule"
      },
      "formula": "sulf_fast",
      "formula_expression": "SULF-FAST = five_or_fewer_years_ago (true 2) + anaphylaxis_angioedema_or_scar (true 2) + treatment_required (true 1); Waldron 2023; max 5; score < 3 low, score ≥ 3 elevated; low_risk_for_testing iff score < 3",
      "max_score": 5,
      "score": 0,
      "risk": "low",
      "low_risk_for_testing": true
    }
  ]
}
```

## Response fields

- `formula` (string): sulf_fast
- `formula_expression` (string): Exact expression used
- `score` (integer): SULF-FAST points 0-5
- `max_score` (integer): Always 5
- `risk` (string): Waldron 2023 risk group: low (score < 3) or elevated (score ≥ 3). Not an allergy diagnosis. Not the Trubiano 2020 four-tier PEN-FAST groups.
- `low_risk_for_testing` (boolean): true iff score < 3 (Waldron 2023 low-risk cutoff). Not a delabeling order and not a substitute for specialist testing when indicated.
- `components` (array): Per-flag points
- `citation` (object): Waldron 2023 JAMA Network Open citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "components": [
    {
      "factor": "five_or_fewer_years_ago",
      "points": 0,
      "present": false
    },
    {
      "factor": "anaphylaxis_angioedema_or_scar",
      "points": 0,
      "present": false
    },
    {
      "factor": "treatment_required",
      "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": "Waldron JL, Rose M, Vogrin S, Krantz MS, Bolotte R, Phillips EJ, Trubiano JA",
    "doi": "10.1001/jamanetworkopen.2023.16776",
    "id": "waldron-2023",
    "pmid": "37273210",
    "source": "JAMA Netw Open. 2023;6(6):e2316776",
    "title": "Development and Validation of a Sulfa Antibiotic Allergy Clinical Decision Rule"
  },
  "formula": "sulf_fast",
  "formula_expression": "SULF-FAST = five_or_fewer_years_ago (true 2) + anaphylaxis_angioedema_or_scar (true 2) + treatment_required (true 1); Waldron 2023; max 5; score < 3 low, score ≥ 3 elevated; low_risk_for_testing iff score < 3",
  "max_score": 5,
  "score": 0,
  "risk": "low",
  "low_risk_for_testing": true
}
```

## Errors

- 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

- [PEN-FAST](https://magentlab.com/docs/pen-fast) — Sum the three Trubiano 2020 PEN-FAST flags for a reported penicillin allergy and return the 0–5 score, published risk group, and low_risk_for_testing (score < 3).

## 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.