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MESS Calculator (Mangled Extremity Severity Score)
x402
MESS Calculator (Mangled Extremity Severity Score) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).
Computes the Johansen 1990 Mangled Extremity Severity Score (MESS) from four caller-assigned inputs: skeletal/soft-tissue energy, limb ischemia, shock, and age, returning the total score and amputation-risk band.
Price / call$0.005
Success—
StatusUnknown
How this service works
Johansen 1990 Mangled Extremity Severity Score (MESS): caller-assigned skeletal/soft-tissue energy 1-4, limb ischemia 1-3 (doubled if ischemia time >6 hours), shock 0-2, and age points (<30 → 0, 30-50 → 1, >50 → 2). Max 14. MESS ≥7 predicted amputation with 100% accuracy in that series (mess_band 0-6 or >=7). Deterministic published arithmetic with citation. Not an amputation or limb-salvage protocol; magent does not examine the limb. Not later papers' cutoff of 8.
Output
Returns the numeric MESS total (integer 0–14), the risk band classification ('0-6' for below threshold or '>=7' for the Johansen 1990 amputation-predicted range), and the underlying component scores. This is deterministic published arithmetic with no clinical examination or limb-salvage recommendation.
Example use cases
Trauma bay limb-salvage documentation
“I need a MESS score for a 55-year-old patient who came in after a motorcycle crash — skeletal/soft-tissue energy is 3 (high energy), limb ischemia is 3 (cool, paralyzed, insensate), ischemia time is under 6 hours, and shock is 2 (persistent systolic below 90). What's the total and risk band?”
Pediatric extremity injury scoring
“Can you compute the Johansen MESS for a 22-year-old with a low-energy injury (skeletal score 1), reduced pulse but normal perfusion (ischemia 1), no ischemia over 6 hours, and blood pressure always above 90 (shock 0)?”
Orthopedic trauma audit tool
“Run a MESS calculation for our audit: patient age 62, skeletal soft-tissue energy 2, limb ischemia score 2 with ischemia time greater than 6 hours, and shock score 1. Show me the score and whether it hits the ≥7 amputation threshold.”
Technical details
Endpoint
GEThttps://api.magentlab.com/api/calc/messWhen to prefer
Use this endpoint when you need fast, deterministic reproduction of the Johansen 1990 MESS formula for trauma documentation, clinical decision support audits, or EHR integration. Prefer it over manual calculation to eliminate arithmetic errors. Note: this implements the original 1990 cutoff of ≥7 (not later papers' cutoff of 8), and does not perform physical examination or make amputation recommendations.
Side effects
- Invalid integer ranges for skeletal_soft_tissue (must be 1-4), limb_ischemia (must be 1-3), or shock (must be 0-2) return a validation error
- Age outside 0-120 integer range returns an error
- Missing required query parameters return a 400-level error
- ischemia_over_6h must be a boolean; non-boolean values cause a parse error
- Network errors or upstream downtime return 5xx responses
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"path": "/api/calc/mess",
"count": 2,
"items": [
{
"age": 25,
"score": 2,
"shock": 0,
"formula": "mess",
"citation": {
"id": "johansen-1990",
"doi": "10.1097/00005373-199005000-00007",
"pmid": "2342140",
"title": "Objective criteria accurately predict amputation following lower extremity trauma",
"source": "J Trauma. 1990;30(5):568-572",
"authors": "Johansen K, Daines M, Howey T, Helfet D, Hansen ST"
},
"max_score": 14,
"mess_band": "0-6",
"age_points": 0,
"components": [
{
"value": 1,
"factor": "skeletal_soft_tissue",
"points": 1,
"present": true
},
{
"value": 1,
"factor": "limb_ischemia",
"points": 1,
"doubled": false,
"present": true
},
{
"value": 0,
"factor": "shock",
"points": 0,
"present": false
},
{
"value": 25,
"factor": "age",
"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.",
"limb_ischemia": 1,
"ischemia_points": 1,
"ischemia_over_6h": false,
"formula_expression": "MESS = skeletal_soft_tissue (1-4) + limb_ischemia (1-3, doubled if ischemia_over_6h) + shock (0-2) + age_points (<30 → 0, 30-50 → 1, >50 → 2); Johansen 1990 band 0-6 / >=7; max 14",
"skeletal_soft_tissue": 1
},
{
"age": 25,
"score": 2,
"shock": 0,
"formula": "mess",
"citation": {
"id": "johansen-1990",
"doi": "10.1097/00005373-199005000-00007",
"pmid": "2342140",
"title": "Objective criteria accurately predict amputation following lower extremity trauma",
"source": "J Trauma. 1990;30(5):568-572",
"authors": "Johansen K, Daines M, Howey T, Helfet D, Hansen ST"
},
"max_score": 14,
"mess_band": "0-6",
"age_points": 0,
"components": [
{
"value": 1,
"factor": "skeletal_soft_tissue",
"points": 1,
"present": true
},
{
"value": 1,
"factor": "limb_ischemia",
"points": 1,
"doubled": false,
"present": true
},
{
"value": 0,
"factor": "shock",
"points": 0,
"present": false
},
{
"value": 25,
"factor": "age",
"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.",
"limb_ischemia": 1,
"ischemia_points": 1,
"ischemia_over_6h": false,
"formula_expression": "MESS = skeletal_soft_tissue (1-4) + limb_ischemia (1-3, doubled if ischemia_over_6h) + shock (0-2) + age_points (<30 → 0, 30-50 → 1, >50 → 2); Johansen 1990 band 0-6 / >=7; max 14",
"skeletal_soft_tissue": 1
}
]
}
}Tags
x402
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