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PERC Rule Calculator (Pulmonary Embolism Rule-Out Criteria)
x402
PERC Rule Calculator (Pulmonary Embolism Rule-Out Criteria) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-10).
Evaluates all eight Kline 2004 PERC criteria to determine whether pulmonary embolism can be ruled out in a low-pretest-probability patient without further workup.
Price / call$0.005
Success—
StatusUnknown
How this service works
Deterministic published-formula arithmetic plus ICD-10-CM, RxNorm, and LOINC. Pay in USDC on Base via x402.
Output
Returns a structured result indicating whether the patient is PERC-negative (all eight criteria satisfied, PE rule-out supported in low-pretest-probability context) or PERC-positive (one or more criteria failed, further workup indicated), along with the pass/fail status of each individual criterion.
Example use cases
ED triage PE rule-out decision
“I have a 38-year-old ED patient with suspected PE and low pretest probability. Heart rate is 92, SpO2 is 96%, age 38, no leg swelling, no hemoptysis, no recent surgery, no prior clots, no hormone use — run the PERC rule and tell me if we can rule out PE without further testing.”
Avoid unnecessary D-dimer in low-risk patient
“My patient is 45 years old, pulse 78, oxygen sat 98%, and negative on all the other PERC flags — no leg swelling, no coughing blood, no recent trauma or surgery, no history of DVT or PE, no estrogen. Does PERC rule out pulmonary embolism so we can skip the D-dimer?”
Clinical documentation support for PE workup
“Document whether PERC criteria are met for a 55-year-old patient with heart rate 95, SpO2 95%, no unilateral leg swelling, no hemoptysis, no recent surgery or trauma, no prior VTE, and no estrogen use — I need to know if PERC is positive or negative.”
Technical details
Endpoint
GEThttps://api.magentlab.com/api/calc/perc?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a deterministic, published PERC rule-out calculation for a patient already assessed as low pretest probability for PE. Prefer this over custom logic or LLM reasoning for clinical decision support where reproducibility and fidelity to the Kline 2004 criteria are required. Not appropriate as a D-dimer substitute protocol, for high-pretest patients, or in altitude-adjusted contexts.
Side effects
- Missing required query parameters (age, heart_rate_bpm, spo2_percent, boolean flags) returns a 400-level error
- Age outside valid range 18-120 or SpO2 outside 50-100 rejected as invalid input
- Heart rate outside 30-220 bpm range rejected
- Boolean fields passed as strings instead of true/false may cause parsing errors
- Caller applying PERC without established low pretest probability yields clinically invalid results (not enforced by API)
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"path": "/api/calc/perc",
"count": 2,
"items": [
{
"formula": "perc",
"citation": {
"id": "kline-2004",
"doi": "10.1111/j.1538-7836.2004.00790.x",
"title": "Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism",
"source": "J Thromb Haemost. 2004;2(8):1247-1255",
"authors": "Kline JA, Mitchell AM, Kabrhel C, Richman PB, Courtney DM"
},
"criteria": [
{
"met": true,
"value": 40,
"factor": "age_lt_50"
},
{
"met": true,
"value": 80,
"factor": "pulse_lt_100"
},
{
"met": true,
"value": 98,
"factor": "sao2_gt_94"
},
{
"met": true,
"factor": "no_unilateral_leg_swelling"
},
{
"met": true,
"factor": "no_hemoptysis"
},
{
"met": true,
"factor": "no_recent_surgery_or_trauma"
},
{
"met": true,
"factor": "no_prior_vte"
},
{
"met": true,
"factor": "no_estrogen_use"
}
],
"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.",
"perc_negative": true,
"formula_expression": "PERC-negative iff age < 50 and pulse < 100 bpm and SaO2 > 94% and no unilateral leg swelling and no hemoptysis and no recent trauma or surgery and no prior PE or DVT and no hormone use"
},
{
"formula": "perc",
"citation": {
"id": "kline-2004",
"doi": "10.1111/j.1538-7836.2004.00790.x",
"title": "Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism",
"source": "J Thromb Haemost. 2004;2(8):1247-1255",
"authors": "Kline JA, Mitchell AM, Kabrhel C, Richman PB, Courtney DM"
},
"criteria": [
{
"met": true,
"value": 40,
"factor": "age_lt_50"
},
{
"met": true,
"value": 80,
"factor": "pulse_lt_100"
},
{
"met": true,
"value": 98,
"factor": "sao2_gt_94"
},
{
"met": true,
"factor": "no_unilateral_leg_swelling"
},
{
"met": true,
"factor": "no_hemoptysis"
},
{
"met": true,
"factor": "no_recent_surgery_or_trauma"
},
{
"met": true,
"factor": "no_prior_vte"
},
{
"met": true,
"factor": "no_estrogen_use"
}
],
"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.",
"perc_negative": true,
"formula_expression": "PERC-negative iff age < 50 and pulse < 100 bpm and SaO2 > 94% and no unilateral leg swelling and no hemoptysis and no recent trauma or surgery and no prior PE or DVT and no hormone use"
}
]
}
}Tags
x402
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