Emergency · LIVE

TRISS (Boyd 1987)

TRISS

Compute Boyd 1987 TRISS probability of survival from mechanism, Champion weighted RTS, ISS, and age using the original Major Trauma Outcome Study coefficients printed with that method.

LIVE $0.005 USDC GET /api/calc/triss

Markdown: /docs/triss.md · Canonical: https://magentlab.com/docs/triss

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

What it computes

Compute Boyd 1987 TRISS probability of survival from mechanism, Champion weighted RTS, ISS, and age using the original Major Trauma Outcome Study coefficients printed with that method.

When to use

When an agent needs the published Boyd 1987 TRISS probability of survival and must not recode GCS/SBP/RR, substitute NISS or ASCOT, or apply Champion 1995 revised coefficients.

When not to use

• Not a medical device. Not a triage order, trauma-activation, or disposition.
• RTS is a caller-assigned Champion weighted Revised Trauma Score (0.0-7.8408). magent does not recode GCS, SBP, or respiratory rate here.
• ISS is a caller-assigned Baker total (1-75). This tool does not compute ISS from AIS, NISS, or ASCOT.
• Boyd 1987 original MTOS coefficients only. Champion 1995 revised TRISS coefficients are not this tool.
• AgeIndex is 0 if age < 55 and 1 if age >= 55 as published. magent does not use continuous age.

Formula

Ps = 1 / (1 + e^(-b)); AgeIndex = 0 if age < 55 else 1; blunt: b = -1.2470 + 0.9544*RTS - 0.0768*ISS - 1.9052*AgeIndex; penetrating: b = -0.6029 + 1.1430*RTS - 0.1516*ISS - 2.6676*AgeIndex (Boyd 1987 original MTOS)

Citation

Title

Evaluating trauma care: the TRISS method. Trauma Score and the Injury Severity Score

Authors

Boyd CR, Tolson MA, Copes WS

Source

J Trauma. 1987;27(4):370-378

DOI

10.1097/00005373-198704000-00005

Worked example

Also searched as

• trauma injury severity score
• TRISS probability of survival
• Boyd TRISS MTOS
• blunt penetrating trauma survival
• RTS ISS AgeIndex
• original MTOS TRISS

Try

Opens the live endpoint. Unpaid browser requests show the paywall; agents should send Accept: application/json.

/api/calc/triss?mechanism=blunt&rts=7.8408&iss=9&age=30

Full URL: https://api.magentlab.com/api/calc/triss?mechanism=blunt&rts=7.8408&iss=9&age=30

Call

Expect HTTP 402 until you retry with PAYMENT-SIGNATURE. Incomplete query params return HTTP 400 before any quote or charge.

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/triss?mechanism=blunt&rts=7.8408&iss=9&age=30"

Parameters

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.

POST /api/calc/triss Max 25 unit_amount + extra_item_amount * (n - 1) extra $0.002 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 (fixture)

{
  "items": [
    {
      "age": "30",
      "iss": "9",
      "mechanism": "blunt",
      "rts": "7.8408"
    },
    {
      "age": "30",
      "iss": "9",
      "mechanism": "blunt",
      "rts": "7.8408"
    }
  ]
}

Open bulk paywall →

Opens a two-item fixture on the API host. Unpaid browsers get the same MetaMask paywall as GET; Pay retries POST with those items.

Example 200 (fixture)

{
  "count": 2,
  "path": "/api/calc/triss",
  "items": [
    {
      "b": 5.5451,
      "age": 30,
      "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": "Boyd CR, Tolson MA, Copes WS",
        "doi": "10.1097/00005373-198704000-00005",
        "id": "boyd-1987",
        "pmid": "3106646",
        "source": "J Trauma. 1987;27(4):370-378",
        "title": "Evaluating trauma care: the TRISS method. Trauma Score and the Injury Severity Score"
      },
      "formula": "triss",
      "formula_expression": "Ps = 1 / (1 + e^(-b)); AgeIndex = 0 if age < 55 else 1; blunt: b = -1.2470 + 0.9544*RTS - 0.0768*ISS - 1.9052*AgeIndex; penetrating: b = -0.6029 + 1.1430*RTS - 0.1516*ISS - 2.6676*AgeIndex (Boyd 1987 original MTOS)",
      "mechanism": "blunt",
      "rts": 7.8408,
      "age_index": 0,
      "iss": 9,
      "survival_probability": 0.9961
    },
    {
      "b": 5.5451,
      "age": 30,
      "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": "Boyd CR, Tolson MA, Copes WS",
        "doi": "10.1097/00005373-198704000-00005",
        "id": "boyd-1987",
        "pmid": "3106646",
        "source": "J Trauma. 1987;27(4):370-378",
        "title": "Evaluating trauma care: the TRISS method. Trauma Score and the Injury Severity Score"
      },
      "formula": "triss",
      "formula_expression": "Ps = 1 / (1 + e^(-b)); AgeIndex = 0 if age < 55 else 1; blunt: b = -1.2470 + 0.9544*RTS - 0.0768*ISS - 1.9052*AgeIndex; penetrating: b = -0.6029 + 1.1430*RTS - 0.1516*ISS - 2.6676*AgeIndex (Boyd 1987 original MTOS)",
      "mechanism": "blunt",
      "rts": 7.8408,
      "age_index": 0,
      "iss": 9,
      "survival_probability": 0.9961
    }
  ]
}

Response

Example JSON

Machine form of the same example. Frozen fixture. Not a live lookup.

{
  "b": 5.5451,
  "age": 30,
  "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": "Boyd CR, Tolson MA, Copes WS",
    "doi": "10.1097/00005373-198704000-00005",
    "id": "boyd-1987",
    "pmid": "3106646",
    "source": "J Trauma. 1987;27(4):370-378",
    "title": "Evaluating trauma care: the TRISS method. Trauma Score and the Injury Severity Score"
  },
  "formula": "triss",
  "formula_expression": "Ps = 1 / (1 + e^(-b)); AgeIndex = 0 if age < 55 else 1; blunt: b = -1.2470 + 0.9544*RTS - 0.0768*ISS - 1.9052*AgeIndex; penetrating: b = -0.6029 + 1.1430*RTS - 0.1516*ISS - 2.6676*AgeIndex (Boyd 1987 original MTOS)",
  "mechanism": "blunt",
  "rts": 7.8408,
  "age_index": 0,
  "iss": 9,
  "survival_probability": 0.9961
}

Client errors (HTTP 400)

Invalid params return 400 without charge. Shared HTTP 402 and 503 meanings: Payments.

Related tools

• RTS — Compute Champion 1989 coded GCS, SBP, and respiratory-rate values, the triage T-RTS sum, and the weighted RTS used for outcome evaluation.
• ISS — Compute the Baker 1974 Injury Severity Score as the sum of squares of the three highest caller-assigned AIS body-region grades, or 75 if any region is AIS 6.

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. Unpaid valid requests return HTTP 402 with a base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote: retry the same PAYMENT-SIGNATURE. Full handshake and shared payment errors: Payments. Stdio MCP: /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.