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Magent Phenytoin Correction Calculator (Sheiner–Tozer / Winter–Tozer)
x402
Magent Phenytoin Correction Calculator (Sheiner–Tozer / Winter–Tozer) 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).
Calculates albumin-adjusted (corrected) total phenytoin concentration using the Sheiner–Tozer or Winter–Tozer formula, with a renal impairment adjustment factor.
Price / call$0.005
Success—
StatusUnknown
How this service works
Sheiner–Tozer / Winter–Tozer albumin-adjusted total phenytoin: Ccorr = Cobs / ((0.2 or 0.1) × albumin_g_dl + 0.1). Renal factor 0.1 when renal_impairment is true. Deterministic published arithmetic with citation; not a free phenytoin level or a dose.
Output
Returns the albumin-adjusted (corrected) total phenytoin concentration in µg/mL, computed using the Sheiner–Tozer formula (renal_impairment=false: Ccorr = Cobs / (0.2 × albumin_g_dl + 0.1)) or the Winter–Tozer renal adjustment (renal_impairment=true: Ccorr = Cobs / (0.1 × albumin_g_dl + 0.1)), along with the formula citation and input echo.
Example use cases
ICU hypoalbuminemia phenytoin adjustment
“My ICU patient's total phenytoin is 9 µg/mL and their albumin is 1.8 g/dL with no renal impairment — what's the corrected phenytoin concentration?”
Dialysis patient therapeutic drug monitoring
“Can you run the Winter–Tozer phenytoin correction for a dialysis patient with an observed phenytoin of 7.5 µg/mL and albumin of 2.5 g/dL? They have end-stage renal disease so use the renal impairment factor.”
Epilepsy clinic medication review
“Our epilepsy clinic patient has a phenytoin level of 14 µg/mL and serum albumin of 3.0 g/dL with normal kidney function — calculate the Sheiner–Tozer corrected phenytoin to see if they're truly in range.”
Technical details
Endpoint
GEThttps://api.magentlab.com/api/calc/phenytoin_correctionWhen to prefer
Use this endpoint when you need a deterministic, citation-backed Sheiner–Tozer / Winter–Tozer phenytoin correction calculation — specifically when a patient has hypoalbuminemia (low albumin) or end-stage renal disease affecting phenytoin protein binding. Prefer this over manual calculation to ensure formula accuracy and auditability. This does not estimate free phenytoin or dose recommendations.
Side effects
- Missing required phenytoin_mcg_ml or renal_impairment parameters returns validation error
- Albumin value out of range (e.g. <1 or >6 g/dL) may return an out-of-range error
- Neither albumin_g_dl nor albumin_g_l provided results in missing-input error
- Non-numeric or malformed query parameter values return 400 Bad Request
- Payment failure (x402) if USDC balance is insufficient
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"path": "/api/calc/phenytoin_correction",
"count": 2,
"items": [
{
"formula": "sheiner_tozer",
"citation": {
"id": "liponi-1984",
"doi": "10.1212/WNL.34.3.395",
"title": "Renal function and therapeutic concentrations of phenytoin",
"source": "Neurology. 1984;34(3):395-397",
"authors": "Liponi DF, Winter ME, Tozer TN"
},
"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.",
"albumin_g_dl": 2,
"binding_factor": 0.2,
"phenytoin_mcg_ml": 8,
"renal_impairment": false,
"formula_expression": "corrected_phenytoin_mcg_ml = phenytoin_mcg_ml / ((binding_factor * albumin_g_dl) + 0.1); binding_factor 0.2, or 0.1 if renal_impairment",
"corrected_phenytoin_mcg_ml": 16
},
{
"formula": "sheiner_tozer",
"citation": {
"id": "liponi-1984",
"doi": "10.1212/WNL.34.3.395",
"title": "Renal function and therapeutic concentrations of phenytoin",
"source": "Neurology. 1984;34(3):395-397",
"authors": "Liponi DF, Winter ME, Tozer TN"
},
"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.",
"albumin_g_dl": 2,
"binding_factor": 0.2,
"phenytoin_mcg_ml": 8,
"renal_impairment": false,
"formula_expression": "corrected_phenytoin_mcg_ml = phenytoin_mcg_ml / ((binding_factor * albumin_g_dl) + 0.1); binding_factor 0.2, or 0.1 if renal_impairment",
"corrected_phenytoin_mcg_ml": 16
}
]
}
}Tags
x402
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