Emergency · LIVE

NEXUS Chest

Apply the Rodriguez 2011 NEXUS Chest decision instrument and return whether the seven low-risk criteria all hold (chest radiography not indicated by this instrument).

LIVE $0.005 USDC GET /api/calc/nexus_chest

Markdown: /docs/nexus-chest.md · Canonical: https://magentlab.com/docs/nexus-chest

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

What it computes

Apply the Rodriguez 2011 NEXUS Chest decision instrument and return whether the seven low-risk criteria all hold (chest radiography not indicated by this instrument).

When to use

When an agent has caller-assigned findings after blunt trauma and needs the published NEXUS Chest selective chest-radiography instrument, not the Hoffman 2000 NEXUS C-spine rule.

When not to use

• Not a diagnosis. magent does not examine the patient or the chest.
• This tool is the Rodriguez 2011 NEXUS Chest decision instrument for selective chest radiography only. It is not the Hoffman 2000 NEXUS C-spine rule and not a NEXUS Chest CT instrument.
• Derivation enrolled blunt trauma age >14. magent does not take numeric age; the caller assigns age >60 as one of the seven criteria.
• The caller assigns all seven criteria. Does not replace imaging when any criterion fails.

Formula

NEXUS Chest low-risk iff no chest pain and no distracting injury and no chest-wall tenderness and no intoxication and age not >60 and no rapid deceleration and no altered mental status

Citation

Title

Derivation of a decision instrument for selective chest radiography in blunt trauma

Authors

Rodriguez RM, Hendey GW, Mower W, et al.

Source

J Trauma. 2011;71(3):549-553

DOI

10.1097/TA.0b013e3181f2ac9d

Worked example

Also searched as

• NEXUS Chest
• NEXUS Chest radiography
• Rodriguez NEXUS Chest
• selective chest radiography
• blunt trauma chest x-ray rule
• NEXUS Chest decision instrument
• NEXUS Chest seven criteria

Try

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

/api/calc/nexus_chest?chest_pain=false&distracting_injury=false&chest_wall_tenderness=false&intoxication=false&age_gt_60=false&rapid_deceleration=false&altered_mental_status=false

Full URL: https://api.magentlab.com/api/calc/nexus_chest?chest_pain=false&distracting_injury=false&chest_wall_tenderness=false&intoxication=false&age_gt_60=false&rapid_deceleration=false&altered_mental_status=false

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/nexus_chest?chest_pain=false&distracting_injury=false&chest_wall_tenderness=false&intoxication=false&age_gt_60=false&rapid_deceleration=false&altered_mental_status=false"

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/nexus_chest 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_gt_60": "false",
      "altered_mental_status": "false",
      "chest_pain": "false",
      "chest_wall_tenderness": "false",
      "distracting_injury": "false",
      "intoxication": "false",
      "rapid_deceleration": "false"
    },
    {
      "age_gt_60": "false",
      "altered_mental_status": "false",
      "chest_pain": "false",
      "chest_wall_tenderness": "false",
      "distracting_injury": "false",
      "intoxication": "false",
      "rapid_deceleration": "false"
    }
  ]
}

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/nexus_chest",
  "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": "Rodriguez RM, Hendey GW, Mower W, et al.",
        "doi": "10.1097/TA.0b013e3181f2ac9d",
        "id": "rodriguez-2011",
        "pmid": "21045745",
        "source": "J Trauma. 2011;71(3):549-553",
        "title": "Derivation of a decision instrument for selective chest radiography in blunt trauma"
      },
      "formula": "nexus_chest",
      "formula_expression": "NEXUS Chest low-risk iff no chest pain and no distracting injury and no chest-wall tenderness and no intoxication and age not >60 and no rapid deceleration and no altered mental status",
      "criteria": [
        {
          "factor": "no_chest_pain",
          "met": true
        },
        {
          "factor": "no_distracting_injury",
          "met": true
        },
        {
          "factor": "no_chest_wall_tenderness",
          "met": true
        },
        {
          "factor": "no_intoxication",
          "met": true
        },
        {
          "factor": "no_age_gt_60",
          "met": true
        },
        {
          "factor": "no_rapid_deceleration",
          "met": true
        },
        {
          "factor": "no_altered_mental_status",
          "met": true
        }
      ],
      "chest_xray_indicated": false,
      "nexus_chest_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": "Rodriguez RM, Hendey GW, Mower W, et al.",
        "doi": "10.1097/TA.0b013e3181f2ac9d",
        "id": "rodriguez-2011",
        "pmid": "21045745",
        "source": "J Trauma. 2011;71(3):549-553",
        "title": "Derivation of a decision instrument for selective chest radiography in blunt trauma"
      },
      "formula": "nexus_chest",
      "formula_expression": "NEXUS Chest low-risk iff no chest pain and no distracting injury and no chest-wall tenderness and no intoxication and age not >60 and no rapid deceleration and no altered mental status",
      "criteria": [
        {
          "factor": "no_chest_pain",
          "met": true
        },
        {
          "factor": "no_distracting_injury",
          "met": true
        },
        {
          "factor": "no_chest_wall_tenderness",
          "met": true
        },
        {
          "factor": "no_intoxication",
          "met": true
        },
        {
          "factor": "no_age_gt_60",
          "met": true
        },
        {
          "factor": "no_rapid_deceleration",
          "met": true
        },
        {
          "factor": "no_altered_mental_status",
          "met": true
        }
      ],
      "chest_xray_indicated": false,
      "nexus_chest_low_risk": true
    }
  ]
}

Response

Example JSON

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

{
  "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": "Rodriguez RM, Hendey GW, Mower W, et al.",
    "doi": "10.1097/TA.0b013e3181f2ac9d",
    "id": "rodriguez-2011",
    "pmid": "21045745",
    "source": "J Trauma. 2011;71(3):549-553",
    "title": "Derivation of a decision instrument for selective chest radiography in blunt trauma"
  },
  "formula": "nexus_chest",
  "formula_expression": "NEXUS Chest low-risk iff no chest pain and no distracting injury and no chest-wall tenderness and no intoxication and age not >60 and no rapid deceleration and no altered mental status",
  "criteria": [
    {
      "factor": "no_chest_pain",
      "met": true
    },
    {
      "factor": "no_distracting_injury",
      "met": true
    },
    {
      "factor": "no_chest_wall_tenderness",
      "met": true
    },
    {
      "factor": "no_intoxication",
      "met": true
    },
    {
      "factor": "no_age_gt_60",
      "met": true
    },
    {
      "factor": "no_rapid_deceleration",
      "met": true
    },
    {
      "factor": "no_altered_mental_status",
      "met": true
    }
  ],
  "chest_xray_indicated": false,
  "nexus_chest_low_risk": true
}

Client errors (HTTP 400)

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

Related tools

• NEXUS C-spine — Apply the Hoffman 2000 NEXUS C-spine rule and return whether the five low-risk criteria all hold (imaging not indicated by this rule).
• Canadian C-spine rule — Apply the Stiell 2001 Canadian C-spine rule and return whether cervical radiography is indicated from caller-assigned age, high-risk factors, low-risk factors, and neck rotation.

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.
• 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.