MAGENT

Infection / VTE · LIVE

4PEPS pretest probability (Roy 2021)

4PEPS

Sum the Roy 2021 Table 3 4-level clinical pretest probability (4PEPS) items and return score and cpp (very_low, low, moderate, or high).

LIVE $0.005 USDC GET /api/calc/4peps

Markdown: /docs/4peps.md · Canonical: https://magentlab.com/docs/4peps

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

What it computes

Sum the Roy 2021 Table 3 4-level clinical pretest probability (4PEPS) items and return score and cpp (very_low, low, moderate, or high).

When to use

When an agent already has the published Table 3 findings assigned and needs the 4PEPS total and clinical probability band, not an imaging or D-dimer order.

When not to use

  • Not a medical device and not an imaging or D-dimer order. magent does not examine the patient or decide “PE most likely”.
  • Age 65–80 and >80 were not independently associated in Table 3; ages ≥65 score 0 for the age item. Heart rate 80–100 was not independently associated; this tool does not add tachycardia points.
  • Immobility is the Table 3 footnote: surgery, lower limb plaster cast, or bedridden more than 3 days for an acute medical condition within the last 4 weeks, as assigned by the caller.
  • Clinical probability cutoffs are Table 3: very_low <0, low 0–5, moderate 6–12, high ≥13. Score may be negative. max_score is 22 when age ≥65 and all positive items fire.

Formula

4PEPS = age (<50 -2, 50-64 -1, ≥65 0) + chronic_respiratory_disease (-1) + heart_rate_bpm (<80 -1) + chest_pain_and_acute_dyspnea (1) + male (2) + hormonal_estrogenic_treatment (2) + personal_history_vte (2) + syncope (2) + immobility_4w (2) + spo2_percent (<95 3) + calf_pain_or_unilateral_edema (3) + pe_most_likely (5); Roy 2021 Table 3; cpp very_low <0, low 0-5, moderate 6-12, high ≥13; max 22 (age ≥65 plus all positive items; score may be negative)

Citation

Title
Derivation and Validation of a 4-Level Clinical Pretest Probability Score for Suspected Pulmonary Embolism to Safely Decrease Imaging Testing
Authors
Roy PM, Friou E, Germeau B, et al.
Source
JAMA Cardiol. 2021;6(6):669-677
DOI
10.1001/jamacardio.2021.0064

Worked example

Age 40 female, no other Table 3 items

Given: age=40calf_pain_or_unilateral_edema=falsechest_pain_and_acute_dyspnea=falsechronic_respiratory_disease=falseheart_rate_bpm=90hormonal_estrogenic_treatment=falseimmobility_4w=falsepe_most_likely=falsepersonal_history_vte=falsesex=femalespo2_percent=98syncope=false

  1. age 40 <50 → −2; heart_rate_bpm 90 is not <80 → 0; spo2_percent 98 is not <95 → 0; female → 0; all flags false
  2. Score = −2 (max 22); cpp = very_low

Age ≥65, male, SpO2 <95, calf finding, PE most likely

Given: age=65calf_pain_or_unilateral_edema=truechest_pain_and_acute_dyspnea=falsechronic_respiratory_disease=falseheart_rate_bpm=90hormonal_estrogenic_treatment=falseimmobility_4w=falsepe_most_likely=truepersonal_history_vte=falsesex=malespo2_percent=90syncope=false

  1. age ≥65 → 0; male → +2; spo2_percent 90 <95 → +3; calf_pain_or_unilateral_edema → +3; pe_most_likely → +5
  2. Score = 13 (max 22); cpp = high

Also searched as

  • 4PEPS
  • 4-level PE pretest probability
  • Roy 4PEPS
  • four-level clinical pretest probability
  • 4PEPS pulmonary embolism
  • clinical pretest probability PE
  • 4-level CPP PE

Try

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

/api/calc/4peps?age=40&sex=female&heart_rate_bpm=90&spo2_percent=98&chronic_respiratory_disease=false&chest_pain_and_acute_dyspnea=false&hormonal_estrogenic_treatment=false&personal_history_vte=false&syncope=false&immobility_4w=false&calf_pain_or_unilateral_edema=false&pe_most_likely=false

Full URL: https://api.magentlab.com/api/calc/4peps?age=40&sex=female&heart_rate_bpm=90&spo2_percent=98&chronic_respiratory_disease=false&chest_pain_and_acute_dyspnea=false&hormonal_estrogenic_treatment=false&personal_history_vte=false&syncope=false&immobility_4w=false&calf_pain_or_unilateral_edema=false&pe_most_likely=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/4peps?age=40&sex=female&heart_rate_bpm=90&spo2_percent=98&chronic_respiratory_disease=false&chest_pain_and_acute_dyspnea=false&hormonal_estrogenic_treatment=false&personal_history_vte=false&syncope=false&immobility_4w=false&calf_pain_or_unilateral_edema=false&pe_most_likely=false"

Parameters

Name Type Required Description
age integer required Age in years (integer 18-120). Roy 2021 Table 3: <50 scores −2; 50-64 scores −1; ≥65 scores 0 (65-80 and >80 were not independently associated).
chronic_respiratory_disease boolean required Chronic respiratory disease (Roy 2021 Table 3). true scores −1. Assigned by the caller. magent does not examine the patient.
heart_rate_bpm integer required Heart rate in beats per minute (integer 30-220). Table 3: <80 scores −1. 80-100 was not independently associated; this tool does not add tachycardia points.
chest_pain_and_acute_dyspnea boolean required Both chest pain and acute dyspnea present as assigned by the caller (Roy 2021 Table 3). true scores +1. magent does not examine the patient.
sex string required · female, male female or male (Roy 2021 Table 3). Male scores +2. Female scores 0. Assigned by the caller.
hormonal_estrogenic_treatment boolean required Hormonal estrogenic treatment as assigned by the caller (Roy 2021 Table 3). true scores +2.
personal_history_vte boolean required Personal history of VTE as assigned by the caller (Roy 2021 Table 3). true scores +2.
syncope boolean required Syncope as assigned by the caller (Roy 2021 Table 3). true scores +2. magent does not examine the patient.
immobility_4w boolean required Immobility within 4 weeks (Roy 2021 Table 3 footnote a): surgery, lower limb plaster cast, or bedridden more than 3 days for an acute medical condition. true scores +2. Assigned by the caller. magent does not examine the patient.
spo2_percent number required Oxygen saturation percent (50-100). Roy 2021 Table 3: <95 scores +3; 95 and above score 0.
calf_pain_or_unilateral_edema boolean required Calf pain and/or unilateral lower-limb edema as assigned by the caller (Roy 2021 Table 3). true scores +3. magent does not examine the patient.
pe_most_likely boolean required PE is the most likely diagnosis as assigned by the caller (Roy 2021 Table 3). true scores +5. magent does not examine the patient or decide PE most likely.

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/4peps 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": "40",
      "calf_pain_or_unilateral_edema": "false",
      "chest_pain_and_acute_dyspnea": "false",
      "chronic_respiratory_disease": "false",
      "heart_rate_bpm": "90",
      "hormonal_estrogenic_treatment": "false",
      "immobility_4w": "false",
      "pe_most_likely": "false",
      "personal_history_vte": "false",
      "sex": "female",
      "spo2_percent": "98",
      "syncope": "false"
    },
    {
      "age": "40",
      "calf_pain_or_unilateral_edema": "false",
      "chest_pain_and_acute_dyspnea": "false",
      "chronic_respiratory_disease": "false",
      "heart_rate_bpm": "90",
      "hormonal_estrogenic_treatment": "false",
      "immobility_4w": "false",
      "pe_most_likely": "false",
      "personal_history_vte": "false",
      "sex": "female",
      "spo2_percent": "98",
      "syncope": "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/4peps",
  "items": [
    {
      "components": [
        {
          "value": 40,
          "factor": "age",
          "points": -2,
          "present": true
        },
        {
          "factor": "chronic_respiratory_disease",
          "points": 0,
          "present": false
        },
        {
          "value": 90,
          "factor": "heart_rate_bpm",
          "points": 0,
          "present": false
        },
        {
          "factor": "chest_pain_and_acute_dyspnea",
          "points": 0,
          "present": false
        },
        {
          "value": "female",
          "factor": "sex",
          "points": 0,
          "present": false
        },
        {
          "factor": "hormonal_estrogenic_treatment",
          "points": 0,
          "present": false
        },
        {
          "factor": "personal_history_vte",
          "points": 0,
          "present": false
        },
        {
          "factor": "syncope",
          "points": 0,
          "present": false
        },
        {
          "factor": "immobility_4w",
          "points": 0,
          "present": false
        },
        {
          "value": 98.0,
          "factor": "spo2_percent",
          "points": 0,
          "present": false
        },
        {
          "factor": "calf_pain_or_unilateral_edema",
          "points": 0,
          "present": false
        },
        {
          "factor": "pe_most_likely",
          "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": "Roy PM, Friou E, Germeau B, et al.",
        "doi": "10.1001/jamacardio.2021.0064",
        "id": "roy-2021",
        "pmid": "33656522",
        "source": "JAMA Cardiol. 2021;6(6):669-677",
        "title": "Derivation and Validation of a 4-Level Clinical Pretest Probability Score for Suspected Pulmonary Embolism to Safely Decrease Imaging Testing"
      },
      "formula": "4peps",
      "formula_expression": "4PEPS = age (<50 -2, 50-64 -1, ≥65 0) + chronic_respiratory_disease (-1) + heart_rate_bpm (<80 -1) + chest_pain_and_acute_dyspnea (1) + male (2) + hormonal_estrogenic_treatment (2) + personal_history_vte (2) + syncope (2) + immobility_4w (2) + spo2_percent (<95 3) + calf_pain_or_unilateral_edema (3) + pe_most_likely (5); Roy 2021 Table 3; cpp very_low <0, low 0-5, moderate 6-12, high ≥13; max 22 (age ≥65 plus all positive items; score may be negative)",
      "max_score": 22,
      "score": -2,
      "cpp": "very_low"
    },
    {
      "components": [
        {
          "value": 40,
          "factor": "age",
          "points": -2,
          "present": true
        },
        {
          "factor": "chronic_respiratory_disease",
          "points": 0,
          "present": false
        },
        {
          "value": 90,
          "factor": "heart_rate_bpm",
          "points": 0,
          "present": false
        },
        {
          "factor": "chest_pain_and_acute_dyspnea",
          "points": 0,
          "present": false
        },
        {
          "value": "female",
          "factor": "sex",
          "points": 0,
          "present": false
        },
        {
          "factor": "hormonal_estrogenic_treatment",
          "points": 0,
          "present": false
        },
        {
          "factor": "personal_history_vte",
          "points": 0,
          "present": false
        },
        {
          "factor": "syncope",
          "points": 0,
          "present": false
        },
        {
          "factor": "immobility_4w",
          "points": 0,
          "present": false
        },
        {
          "value": 98.0,
          "factor": "spo2_percent",
          "points": 0,
          "present": false
        },
        {
          "factor": "calf_pain_or_unilateral_edema",
          "points": 0,
          "present": false
        },
        {
          "factor": "pe_most_likely",
          "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": "Roy PM, Friou E, Germeau B, et al.",
        "doi": "10.1001/jamacardio.2021.0064",
        "id": "roy-2021",
        "pmid": "33656522",
        "source": "JAMA Cardiol. 2021;6(6):669-677",
        "title": "Derivation and Validation of a 4-Level Clinical Pretest Probability Score for Suspected Pulmonary Embolism to Safely Decrease Imaging Testing"
      },
      "formula": "4peps",
      "formula_expression": "4PEPS = age (<50 -2, 50-64 -1, ≥65 0) + chronic_respiratory_disease (-1) + heart_rate_bpm (<80 -1) + chest_pain_and_acute_dyspnea (1) + male (2) + hormonal_estrogenic_treatment (2) + personal_history_vte (2) + syncope (2) + immobility_4w (2) + spo2_percent (<95 3) + calf_pain_or_unilateral_edema (3) + pe_most_likely (5); Roy 2021 Table 3; cpp very_low <0, low 0-5, moderate 6-12, high ≥13; max 22 (age ≥65 plus all positive items; score may be negative)",
      "max_score": 22,
      "score": -2,
      "cpp": "very_low"
    }
  ]
}

Response

Field Type Description
formula string 4peps
formula_expression string Exact expression used
score integer 4PEPS points. May be negative. Theoretical maximum 22 when age ≥65 and all positive items fire.
max_score integer Always 22 (age ≥65 plus all positive Table 3 items; score may be negative)
cpp string Roy 2021 Table 3 clinical probability: very_low when score <0, low when 0-5, moderate when 6-12, high when ≥13. Not a diagnosis.
components array Per-item points
citation object Roy 2021 JAMA Cardiology citation
disclaimer string Not-a-device notice

Example JSON

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

{
  "components": [
    {
      "value": 40,
      "factor": "age",
      "points": -2,
      "present": true
    },
    {
      "factor": "chronic_respiratory_disease",
      "points": 0,
      "present": false
    },
    {
      "value": 90,
      "factor": "heart_rate_bpm",
      "points": 0,
      "present": false
    },
    {
      "factor": "chest_pain_and_acute_dyspnea",
      "points": 0,
      "present": false
    },
    {
      "value": "female",
      "factor": "sex",
      "points": 0,
      "present": false
    },
    {
      "factor": "hormonal_estrogenic_treatment",
      "points": 0,
      "present": false
    },
    {
      "factor": "personal_history_vte",
      "points": 0,
      "present": false
    },
    {
      "factor": "syncope",
      "points": 0,
      "present": false
    },
    {
      "factor": "immobility_4w",
      "points": 0,
      "present": false
    },
    {
      "value": 98.0,
      "factor": "spo2_percent",
      "points": 0,
      "present": false
    },
    {
      "factor": "calf_pain_or_unilateral_edema",
      "points": 0,
      "present": false
    },
    {
      "factor": "pe_most_likely",
      "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": "Roy PM, Friou E, Germeau B, et al.",
    "doi": "10.1001/jamacardio.2021.0064",
    "id": "roy-2021",
    "pmid": "33656522",
    "source": "JAMA Cardiol. 2021;6(6):669-677",
    "title": "Derivation and Validation of a 4-Level Clinical Pretest Probability Score for Suspected Pulmonary Embolism to Safely Decrease Imaging Testing"
  },
  "formula": "4peps",
  "formula_expression": "4PEPS = age (<50 -2, 50-64 -1, ≥65 0) + chronic_respiratory_disease (-1) + heart_rate_bpm (<80 -1) + chest_pain_and_acute_dyspnea (1) + male (2) + hormonal_estrogenic_treatment (2) + personal_history_vte (2) + syncope (2) + immobility_4w (2) + spo2_percent (<95 3) + calf_pain_or_unilateral_edema (3) + pe_most_likely (5); Roy 2021 Table 3; cpp very_low <0, low 0-5, moderate 6-12, high ≥13; max 22 (age ≥65 plus all positive items; score may be negative)",
  "max_score": 22,
  "score": -2,
  "cpp": "very_low"
}

Client errors (HTTP 400)

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

HTTP Code When
400 invalid_age age must be an integer from 18 to 120 Returned before settlement; you are not charged.
400 invalid_sex sex must be female or male Returned before settlement; you are not charged.
400 invalid_heart_rate heart_rate_bpm must be an integer from 30 to 220 Returned before settlement; you are not charged.
400 invalid_spo2 spo2_percent must be a number from 50 to 100. Returned before settlement; you are not charged.
400 invalid_flag boolean clinical flags must be true or false Returned before settlement; you are not charged.
400 invalid_items POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
400 invalid_item_count items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
400 invalid_item each items entry must be a JSON object Returned before settlement; you are not charged.

Related tools

  • PERC rule — Apply the Kline 2004 eight-factor pulmonary embolism rule-out criteria and return whether all eight are met (PERC-negative).
  • YEARS algorithm — Apply the van der Hulle 2017 YEARS algorithm: count three caller-assigned items and return whether PE is excluded at the published D-dimer threshold.
  • Wells PE — Compute the Wells pulmonary-embolism probability score and return three-tier and two-tier bands.
  • Revised Geneva score — Compute the Le Gal 2006 revised Geneva score for suspected pulmonary embolism in the emergency department from age, heart rate, and six caller-assigned findings.

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.