Fractional Excretion of Sodium (FENa) Calculator

Calculate FENa = (urine Na × plasma Cr) / (plasma Na × urine Cr) × 100 — differentiates pre-renal from intrinsic AKI.

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Clinical Guidance

BMI is a screening measure of body size, not a direct measure of body fat. The standard WHO categories are underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obese (≥30).

BMI can overestimate body fat in athletes with high muscle mass and underestimate it in older adults with low muscle mass. Interpret it alongside waist circumference and clinical context rather than as a standalone diagnosis.

⚕ Clinical Disclaimer: These calculators are for educational and reference purposes only. Always verify results with qualified clinical judgment and current clinical guidelines. Do not use as a sole basis for medical decisions.
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How It Works

Calculate FENa = (urine Na × plasma Cr) / (plasma Na × urine Cr) × 100 — differentiates pre-renal from intrinsic AKI

Each component has a specific meaning:

  • Intrinsic AKI — The intrinsic aki recorded for the scenario being assessed.

Note: Interpret the fena calculator result against the thresholds and context described above.

How to Use

Enter the intrinsic AKI for the scenario you are assessing. Calculate FENa = (urine Na × plasma Cr) / (plasma Na × urine Cr) × 100 — differentiates pre-renal from intrinsic AKI. Use the fena calculator result to inform your calculation.

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