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Sign Up Fractional Na⁺ Excretion
The fractional excretion of sodium (FeNa) is the fraction of the sodium filtered by the kidney that is excreted in urine. The FeNa can be used to distinguish between prerenal (0.03) causes of oliguric acute kidney injury.
FeNa =
Urine Na × Serum Cr Serum Na × Urine Cr