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Kocher Score for Septic Arthritis vs Transient Synovitis (Pediatric Hip)
x402
Kocher Score for Septic Arthritis vs Transient Synovitis (Pediatric Hip) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).
Computes the Kocher 1999 four-predictor clinical decision score for differentiating septic arthritis from transient synovitis in children with irritable hip, returning the published predicted probability of septic arthritis.
Price / call$0.005
Success—
StatusUnknown
How this service works
Kocher 1999 four predictors for children with irritable hip: history of fever (oral temperature >38.5 C), non-weight-bearing, ESR >=40 mm/h, and serum WBC >12000/uL; 1 point each, max 4. Returns published predicted probability of septic arthritis vs transient synovitis. Deterministic published score with citation; not a diagnosis, not Caird CRP, not adults, and not an aspiration order.
Output
Returns the computed Kocher score (integer 0–4), the published predicted probability of septic arthritis corresponding to that score (from Kocher 1999), and a citation. The result is a deterministic lookup of published data — not a diagnosis, not the Caird CRP-extended score, not applicable to adults, and does not constitute an aspiration order.
Example use cases
ED triage for pediatric hip pain
“I have a child in the ED with hip pain. They're non-weight-bearing, had a fever of 38.9°C, ESR is 40 mm/h, and WBC is 11,800/µL. Run the Kocher score and tell me the septic arthritis probability.”
All four predictors present high-risk case
“A 5-year-old is presenting with irritable hip. History of fever yes, non-weight-bearing yes, ESR is 65 mm/h, WBC is 15,000/µL. Calculate the Kocher 1999 score and give me the published predicted probability of septic arthritis.”
Low-risk transient synovitis scenario
“A 9-year-old with hip pain is afebrile, weight-bearing, ESR is 20 mm/h, and WBC is 8,500/µL. What does the Kocher score say about the likelihood this is septic arthritis versus transient synovitis?”
Technical details
Endpoint
GEThttps://api.magentlab.com/api/calc/kocherWhen to prefer
Use this endpoint when you need the original Kocher 1999 four-predictor score specifically — not the Caird et al. CRP-extended version. It is appropriate only for pediatric patients with irritable hip being evaluated for septic arthritis versus transient synovitis. Prefer this over manual lookup when integrating clinical decision support into an agentic workflow, EHR assistant, or medical education tool. Do not use for adults or as a substitute for clinical judgment or aspiration.
Side effects
- Missing required parameters (history_of_fever, non_weight_bearing, esr_mm_h) returns a validation error
- ESR value outside valid range (1.0–150.0 mm/h) may be rejected
- WBC value outside valid range returns error
- Providing both wbc_ul and wbc_k_ul may cause ambiguity; only one should be provided
- Payment not included or insufficient USDC results in 402 Payment Required
- Score is inapplicable to adults or to the Caird CRP-modified criteria — misuse yields a valid but clinically inappropriate result
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"path": "/api/calc/kocher",
"count": 2,
"items": [
{
"score": 0,
"wbc_ul": 8000,
"formula": "kocher",
"citation": {
"id": "kocher-1999",
"doi": "10.2106/00004623-199912000-00002",
"pmid": "10608376",
"title": "Differentiating between septic arthritis and transient synovitis of the hip in children: an evidence-based clinical prediction algorithm",
"source": "J Bone Joint Surg Am. 1999;81(12):1662-1670",
"authors": "Kocher MS, Zurakowski D, Kasser JR"
},
"esr_mm_h": 20,
"max_score": 4,
"components": [
{
"factor": "history_of_fever",
"points": 0,
"present": false
},
{
"factor": "non_weight_bearing",
"points": 0,
"present": false
},
{
"value": 20,
"factor": "esr_ge_40",
"points": 0,
"present": false
},
{
"value": 8000,
"factor": "wbc_gt_12000",
"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.",
"formula_expression": "Kocher = history_of_fever + non_weight_bearing + (esr_mm_h >= 40) + (wbc_ul > 12000); each 1; max 4; predicted probability 0:<0.2% 1:3.0% 2:40.0% 3:93.1% 4:99.6%",
"predicted_probability": "<0.2%"
},
{
"score": 0,
"wbc_ul": 8000,
"formula": "kocher",
"citation": {
"id": "kocher-1999",
"doi": "10.2106/00004623-199912000-00002",
"pmid": "10608376",
"title": "Differentiating between septic arthritis and transient synovitis of the hip in children: an evidence-based clinical prediction algorithm",
"source": "J Bone Joint Surg Am. 1999;81(12):1662-1670",
"authors": "Kocher MS, Zurakowski D, Kasser JR"
},
"esr_mm_h": 20,
"max_score": 4,
"components": [
{
"factor": "history_of_fever",
"points": 0,
"present": false
},
{
"factor": "non_weight_bearing",
"points": 0,
"present": false
},
{
"value": 20,
"factor": "esr_ge_40",
"points": 0,
"present": false
},
{
"value": 8000,
"factor": "wbc_gt_12000",
"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.",
"formula_expression": "Kocher = history_of_fever + non_weight_bearing + (esr_mm_h >= 40) + (wbc_ul > 12000); each 1; max 4; predicted probability 0:<0.2% 1:3.0% 2:40.0% 3:93.1% 4:99.6%",
"predicted_probability": "<0.2%"
}
]
}
}Tags
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