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FENa Calculator (Fractional Excretion of Sodium)

Health & Fitness

Calculate the fractional excretion of sodium (FENa) used to help classify acute kidney injury.

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mg/dL
0.1 mg/dL15 mg/dL
mEq/L
0 mEq/L300 mEq/L
mEq/L
100 mEq/L180 mEq/L
mg/dL
1 mg/dL400 mg/dL

FENa

0.48

Fractional excretion of sodium. Educational reference only, not a substitute for clinical judgment.

Interpretation

General interpretation, useful mainly in acute kidney injury and not in patients on diuretics. Under 1% - suggests a prerenal cause

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Odeh Ahwal

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Odeh Ahwal
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Frequently Asked Questions

What is FENa used for?

FENa helps distinguish the cause of acute kidney injury, indicating whether reduced kidney function is more likely from reduced blood flow (prerenal), direct kidney damage (intrinsic renal), or a blockage in the urinary tract (postrenal).

When should FENa not be used?

FENa is only reliable in acute kidney injury, not chronic kidney disease, and its interpretation is unreliable in patients currently taking diuretics, since diuretics independently increase sodium excretion.

How is FENa different from urine sodium alone?

FENa accounts for both sodium and creatinine handling by the kidney, making it a more specific indicator than urine sodium alone, which can be affected by many other factors.

Is this calculator a substitute for medical advice?

No. This is an educational reference implementation of the standard FENa formula, not a substitute for a physicians clinical assessment.

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