Fractional Excretion of Sodium
Separates pre-renal from intrinsic acute kidney injury.
When to use it. Working out the cause of oliguric acute kidney injury.
تُعرض معلومات السلامة الطبية في هذه الصفحة بالإنجليزية. لم يراجعها بعد طبيب يقرأ العربية، والاعتماد على ترجمة لم يتحقق منها أحد ليس آمنًا.
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Limits of this score. FENa is unreliable on diuretics — a loop diuretic forces sodium out and pushes it above 1% whatever the cause; use the fractional excretion of urea instead there. It is also misleading in contrast nephropathy, rhabdomyolysis and glomerulonephritis, all of which can be pre-renal-looking, and in chronic kidney disease.
Sources
- Espinel CH. The FENa test: use in the differential diagnosis of acute renal failure. JAMA 1976;236:579–81.
- Carvounis CP, Nisar S, Guro-Razuman S. Significance of the fractional excretion of urea in the differential diagnosis of acute renal failure. Kidney Int 2002;62:2223–9.
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Educational use only — not medical advice. Never a substitute for clinical judgement.