Calculator
Fractional Excretion of Sodium (FENa) Calculator
Calculate FENa to help distinguish prerenal from intrinsic acute kidney injury.
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All fields required unless notedEnter your values and press Calculate to see the result.
Formula & Clinical Notes
Formula
FENa = (UNa × SCr) / (SNa × UCr) × 100
Clinical Notes
In acute kidney injury, FENa < 1% suggests prerenal azotemia while FENa > 2% suggests intrinsic renal injury (acute tubular necrosis). Values are unreliable with diuretic use and in chronic kidney disease. In these settings FEUrea may be more informative.
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