Nephrology

Fractional Excretion of Urea (FEUrea)

Pre-renal vs intrinsic AKI (useful on diuretics).

Education and reference only. Not a substitute for clinical judgement, local policy or product labelling. Always verify before clinical use. Values are calculated in your browser and never stored.

When to use

Use in AKI to distinguish pre-renal from intrinsic causes, especially when the patient is on diuretics (which invalidate FENa).

Why use

FEUrea is more reliable than FENa in patients taking diuretics.

Critical actions

Use consistent urea and creatinine units (ratios cancel). Preferred over FENa when the patient is on diuretics.

Evidence & references

Carvounis CP et al. Significance of the fractional excretion of urea in the differential diagnosis of acute renal failure. Kidney Int. 2002.

Related calculators

Need a calculator we don't have — or a custom tool?

We build evidence-led clinical calculators, dashboards and reference tools for teams.

Request a Custom Tool ☎ +44 7448 439750