Neurology · LIVE

IMPACT TBI prognostic score

IMPACT

Compute the Steyerberg 2008 IMPACT points and 6-month mortality and unfavorable-outcome probabilities from the printed Figure 1 score chart and logistic LPs. model is required (core, extended, or lab).

LIVE $0.005 USDC GET /api/calc/impact

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

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

What it computes

Compute the Steyerberg 2008 IMPACT points and 6-month mortality and unfavorable-outcome probabilities from the printed Figure 1 score chart and logistic LPs. model is required (core, extended, or lab).

When to use

When an agent already has admission age, GCS motor, and pupils (and CT / hypoxia / hypotension / labs when using those models) and needs the published IMPACT probabilities. Not MRC CRASH, not a GCS conversion, and not a diagnosis.

When not to use

• Not a medical device. Not a diagnosis, triage, ICU, or withdrawal-of-care decision.
• Not MRC CRASH (Perel 2008). magent crash is Extermann 2012 chemotherapy CRASH.
• Age, motor, pupils, hypoxia, hypotension, Marshall CT, tSAH, EDH, glucose, and hemoglobin are caller-assigned. magent does not examine the patient, read the scan, or assay labs.
• Motor 9 is the published untestable/missing token. magent does not infer motor from a narrative.

Formula

IMPACT (Steyerberg 2008 Fig 1): core = age(<=30:0, 31-39:1, 40-49:2, 50-59:3, 60-69:4, >=70:5) + motor(1-2:6, 3:4, 4:2, 5-6:0, 9:3) + pupils(both:0, one:2, none:4); extended = core + hypoxia(yes/suspected:1) + hypotension(yes/suspected:2) + marshall(I:-2, II:0, III-VI:2) + tSAH(yes:2) + EDH(yes:-2); lab = extended + glucose_mmol_l(<6:0, 6-8.9:1, 9-11.9:2, 12-14.9:3, >=15:4) + hb_g_dl(<9:3, 9-11.9:2, 12-14.9:1, >=15:0); p = 1/(1+e^(-LP)); LPcore mort=-2.55+0.275*sum; LPcore unfav=-1.62+0.299*sum; LPext mort=-2.98+0.256*sum; LPext unfav=-2.10+0.276*sum; LPlab mort=-3.42+0.216*sum; LPlab unfav=-2.82+0.257*sum; 6-month percent 1 decimal; not MRC CRASH

Citation

Title

Predicting outcome after traumatic brain injury: development and international validation of prognostic scores based on admission characteristics

Authors

Steyerberg EW, Mushkudiani N, Perel P, Butcher I, Lu J, McHugh GS, Murray GD, Marmarou A, Roberts I, Habbema JDF, Maas AIR

Source

PLoS Med. 2008;5(8):e165

DOI

10.1371/journal.pmed.0050165

Worked example

Also searched as

• IMPACT score
• IMPACT TBI
• Steyerberg IMPACT
• traumatic brain injury prognosis
• IMPACT core model
• IMPACT extended model
• IMPACT lab model
• 6-month TBI outcome
• Marshall CT IMPACT
• International Mission for Prognosis

Try

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

/api/calc/impact?age=35&motor_score=3&pupillary_reactivity=both&model=core

Full URL: https://api.magentlab.com/api/calc/impact?age=35&motor_score=3&pupillary_reactivity=both&model=core

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/impact?age=35&motor_score=3&pupillary_reactivity=both&model=core"

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/impact 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": "35",
      "model": "core",
      "motor_score": "3",
      "pupillary_reactivity": "both"
    },
    {
      "age": "35",
      "model": "core",
      "motor_score": "3",
      "pupillary_reactivity": "both"
    }
  ]
}

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/impact",
  "items": [
    {
      "components": [
        {
          "value": 35,
          "factor": "age",
          "points": 1,
          "present": true
        },
        {
          "value": 3,
          "factor": "motor_score",
          "points": 4,
          "present": true
        },
        {
          "value": "both",
          "factor": "pupillary_reactivity",
          "points": 0,
          "present": false
        }
      ],
      "age": 35,
      "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": "Steyerberg EW, Mushkudiani N, Perel P, Butcher I, Lu J, McHugh GS, Murray GD, Marmarou A, Roberts I, Habbema JDF, Maas AIR",
        "doi": "10.1371/journal.pmed.0050165",
        "id": "steyerberg-2008-impact",
        "pmid": "18640954",
        "source": "PLoS Med. 2008;5(8):e165",
        "title": "Predicting outcome after traumatic brain injury: development and international validation of prognostic scores based on admission characteristics"
      },
      "formula": "impact",
      "formula_expression": "IMPACT (Steyerberg 2008 Fig 1): core = age(<=30:0, 31-39:1, 40-49:2, 50-59:3, 60-69:4, >=70:5) + motor(1-2:6, 3:4, 4:2, 5-6:0, 9:3) + pupils(both:0, one:2, none:4); extended = core + hypoxia(yes/suspected:1) + hypotension(yes/suspected:2) + marshall(I:-2, II:0, III-VI:2) + tSAH(yes:2) + EDH(yes:-2); lab = extended + glucose_mmol_l(<6:0, 6-8.9:1, 9-11.9:2, 12-14.9:3, >=15:4) + hb_g_dl(<9:3, 9-11.9:2, 12-14.9:1, >=15:0); p = 1/(1+e^(-LP)); LPcore mort=-2.55+0.275*sum; LPcore unfav=-1.62+0.299*sum; LPext mort=-2.98+0.256*sum; LPext unfav=-2.10+0.276*sum; LPlab mort=-3.42+0.216*sum; LPlab unfav=-2.82+0.257*sum; 6-month percent 1 decimal; not MRC CRASH",
      "max_score": 15,
      "score": 5,
      "linear_predictor_mortality": -1.175,
      "linear_predictor_unfavorable": -0.125,
      "model": "core",
      "mortality_6_month_percent": 23.6,
      "motor_score": 3,
      "pupillary_reactivity": "both",
      "sum_core": 5,
      "unfavorable_6_month_percent": 46.9
    },
    {
      "components": [
        {
          "value": 35,
          "factor": "age",
          "points": 1,
          "present": true
        },
        {
          "value": 3,
          "factor": "motor_score",
          "points": 4,
          "present": true
        },
        {
          "value": "both",
          "factor": "pupillary_reactivity",
          "points": 0,
          "present": false
        }
      ],
      "age": 35,
      "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": "Steyerberg EW, Mushkudiani N, Perel P, Butcher I, Lu J, McHugh GS, Murray GD, Marmarou A, Roberts I, Habbema JDF, Maas AIR",
        "doi": "10.1371/journal.pmed.0050165",
        "id": "steyerberg-2008-impact",
        "pmid": "18640954",
        "source": "PLoS Med. 2008;5(8):e165",
        "title": "Predicting outcome after traumatic brain injury: development and international validation of prognostic scores based on admission characteristics"
      },
      "formula": "impact",
      "formula_expression": "IMPACT (Steyerberg 2008 Fig 1): core = age(<=30:0, 31-39:1, 40-49:2, 50-59:3, 60-69:4, >=70:5) + motor(1-2:6, 3:4, 4:2, 5-6:0, 9:3) + pupils(both:0, one:2, none:4); extended = core + hypoxia(yes/suspected:1) + hypotension(yes/suspected:2) + marshall(I:-2, II:0, III-VI:2) + tSAH(yes:2) + EDH(yes:-2); lab = extended + glucose_mmol_l(<6:0, 6-8.9:1, 9-11.9:2, 12-14.9:3, >=15:4) + hb_g_dl(<9:3, 9-11.9:2, 12-14.9:1, >=15:0); p = 1/(1+e^(-LP)); LPcore mort=-2.55+0.275*sum; LPcore unfav=-1.62+0.299*sum; LPext mort=-2.98+0.256*sum; LPext unfav=-2.10+0.276*sum; LPlab mort=-3.42+0.216*sum; LPlab unfav=-2.82+0.257*sum; 6-month percent 1 decimal; not MRC CRASH",
      "max_score": 15,
      "score": 5,
      "linear_predictor_mortality": -1.175,
      "linear_predictor_unfavorable": -0.125,
      "model": "core",
      "mortality_6_month_percent": 23.6,
      "motor_score": 3,
      "pupillary_reactivity": "both",
      "sum_core": 5,
      "unfavorable_6_month_percent": 46.9
    }
  ]
}

Response

Example JSON

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

{
  "components": [
    {
      "value": 35,
      "factor": "age",
      "points": 1,
      "present": true
    },
    {
      "value": 3,
      "factor": "motor_score",
      "points": 4,
      "present": true
    },
    {
      "value": "both",
      "factor": "pupillary_reactivity",
      "points": 0,
      "present": false
    }
  ],
  "age": 35,
  "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": "Steyerberg EW, Mushkudiani N, Perel P, Butcher I, Lu J, McHugh GS, Murray GD, Marmarou A, Roberts I, Habbema JDF, Maas AIR",
    "doi": "10.1371/journal.pmed.0050165",
    "id": "steyerberg-2008-impact",
    "pmid": "18640954",
    "source": "PLoS Med. 2008;5(8):e165",
    "title": "Predicting outcome after traumatic brain injury: development and international validation of prognostic scores based on admission characteristics"
  },
  "formula": "impact",
  "formula_expression": "IMPACT (Steyerberg 2008 Fig 1): core = age(<=30:0, 31-39:1, 40-49:2, 50-59:3, 60-69:4, >=70:5) + motor(1-2:6, 3:4, 4:2, 5-6:0, 9:3) + pupils(both:0, one:2, none:4); extended = core + hypoxia(yes/suspected:1) + hypotension(yes/suspected:2) + marshall(I:-2, II:0, III-VI:2) + tSAH(yes:2) + EDH(yes:-2); lab = extended + glucose_mmol_l(<6:0, 6-8.9:1, 9-11.9:2, 12-14.9:3, >=15:4) + hb_g_dl(<9:3, 9-11.9:2, 12-14.9:1, >=15:0); p = 1/(1+e^(-LP)); LPcore mort=-2.55+0.275*sum; LPcore unfav=-1.62+0.299*sum; LPext mort=-2.98+0.256*sum; LPext unfav=-2.10+0.276*sum; LPlab mort=-3.42+0.216*sum; LPlab unfav=-2.82+0.257*sum; 6-month percent 1 decimal; not MRC CRASH",
  "max_score": 15,
  "score": 5,
  "linear_predictor_mortality": -1.175,
  "linear_predictor_unfavorable": -0.125,
  "model": "core",
  "mortality_6_month_percent": 23.6,
  "motor_score": 3,
  "pupillary_reactivity": "both",
  "sum_core": 5,
  "unfavorable_6_month_percent": 46.9
}

Client errors (HTTP 400)

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

Related tools

• Glasgow Coma Scale — Compute the Glasgow Coma Scale as the sum of caller-assigned eye, verbal, and motor integers. The 1974 or 1976 edition is required.
• GCS-Pupils — Return the Brennan 2018 GCS-Pupils index as caller-assigned total GCS 3-15 minus pupil reactivity score (unreactive pupils 0, 1, or 2).
• FOUR score — Compute the FOUR score as the sum of caller-assigned eye, motor, brainstem, and respiration integers 0-4.

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.