Clinical use
Use this calculator for differentiates prerenal vs intrinsic renal aki in therenal workflow. It is decision support and should be interpreted with the patient context, local protocols, and clinician judgment.
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Renal
Fractional Excretion of Sodium Calculator
Differentiates prerenal vs intrinsic renal AKI
Calculate FENa
Interpretation
<1%: prerenal. >2%: intrinsic renal (ATN). Unreliable on diuretics — use FEUrea instead. Only validated in oliguric AKI.
Required inputs
- Urine Na
- Serum Na
- Urine Creatinine
- Serum Creatinine
Evidence and limitations
This page cites 1 published reference. Confirm units and inclusion criteria before applying the output; calculators do not replace assessment, escalation, or local policy.
References
- Espinel CH. JAMA 1976;236:579-581
Frequently asked questions
What is the Fractional Excretion of Sodium?
Fractional Excretion of Sodium is a clinical calculator used for Differentiates prerenal vs intrinsic renal AKI.
How do I interpret the Fractional Excretion of Sodium?
<1%: prerenal. >2%: intrinsic renal (ATN). Unreliable on diuretics — use FEUrea instead. Only validated in oliguric AKI.
What inputs are required for the Fractional Excretion of Sodium?
Required inputs include Urine Na, Serum Na, Urine Creatinine, Serum Creatinine.
What is the evidence behind the Fractional Excretion of Sodium?
The Fractional Excretion of Sodium page cites Espinel CH. JAMA 1976;236:579-581.
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