Corrected Phenytoin Calculator
corrected phenytoin calculator. Get instant, accurate results. Enter values for instant results with step-by-step formulas.
Reviewed by Rahul Singh, Health & Wellness Specialist
Formula
Winter-Tozer: Corrected = Measured / (0.2 x Albumin + 0.1) | Renal: Corrected = Measured / (0.1 x Albumin + 0.1)
Phenytoin is highly protein-bound (~90%). Low albumin increases free (active) drug fraction. The Winter-Tozer equation corrects measured levels to estimate what the total would be with normal binding. Renal impairment further reduces binding.
Worked Examples
Example 1: Low albumin patient
Problem:Measured 8 mcg/mL, albumin 2.5 g/dL, no renal impairment
Solution:Corrected = 8 / (0.2 x 2.5 + 0.1) = 8 / 0.6 = 13.3 mcg/mL
Result:Corrected: 13.3 mcg/mL (Therapeutic)
Frequently Asked Questions
How are corrected lab values calculated?
Some lab values need correction for patient factors. Corrected calcium = measured calcium + 0.8 * (4.0 - albumin). Corrected sodium for hyperglycemia: add 1.6 mEq/L for every 100 mg/dL glucose above 100. Corrected QTc uses Bazett formula: QTc = QT / sqrt(RR interval). These corrections improve clinical accuracy.
Reviewed by Rahul Singh, Health & Wellness Specialist · Editorial policy