💊 Corrected Phenytoin (Albumin)
Adjust a total phenytoin level for hypoalbuminaemia with the Sheiner-Tozer equation.
Clinical takeaway
Low albumin raises the free fraction at a given total level.
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When to use
Interpret phenytoin concentrations when albumin is low.
How it works
Corrected = level / (0.2 × albumin + 0.1); use 0.1 instead of 0.2 if CrCl < 20 mL/min or ESRD. Therapeutic 10–20 µg/mL.
Key points
- Low albumin raises the free fraction at a given total level.
- A measured free phenytoin level is preferred when available.
- Especially important in renal failure.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Measured total phenytoin | 8 µg/mL |
|---|---|
| Albumin | 2.5 g/dL |
| CrCl < 20 mL/min (or ESRD) | No |
→Corrected phenytoin13.3µg/mL
- Therapeutic range：10–20 µg/mL (total)
- Formula：level / (0.2 × albumin + 0.1)
| Measured total phenytoin | 8 µg/mL |
|---|---|
| Albumin | 2.5 g/dL |
| CrCl < 20 mL/min (or ESRD) | Yes |
→Corrected phenytoin22.9µg/mL
- Therapeutic range：10–20 µg/mL (total)
- Formula：level / (0.1 × albumin + 0.1)
Frequently asked questions
- What is Corrected Phenytoin (Albumin)?
- Adjust a total phenytoin level for hypoalbuminaemia with the Sheiner-Tozer equation.
- How is Corrected Phenytoin (Albumin) calculated? What is the core formula?
- Corrected = level / (0.2 × albumin + 0.1); use 0.1 instead of 0.2 if CrCl < 20 mL/min or ESRD. Therapeutic 10–20 µg/mL.
- When is Corrected Phenytoin (Albumin) used?
- Interpret phenytoin concentrations when albumin is low.
- What are the key clinical points for Corrected Phenytoin (Albumin)?
- Low albumin raises the free fraction at a given total level. A measured free phenytoin level is preferred when available. Especially important in renal failure.
- What are the limits and cautions when using Corrected Phenytoin (Albumin)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is Corrected Phenytoin (Albumin) calculated in practice? Can you show a worked example?
- Inputs: Measured total phenytoin 8 µg/mL, Albumin 2.5 g/dL, CrCl < 20 mL/min (or ESRD) No → Result: Corrected phenytoin 13.3 µg/mL（Therapeutic range: 10–20 µg/mL (total), Formula: level / (0.2 × albumin + 0.1)） Inputs: Measured total phenytoin 8 µg/mL, Albumin 2.5 g/dL, CrCl < 20 mL/min (or ESRD) Yes → Result: Corrected phenytoin 22.9 µg/mL（Therapeutic range: 10–20 µg/mL (total), Formula: level / (0.1 × albumin + 0.1)）