This version was machine-translated from German and has not been medically reviewed. The authoritative version is the German version.

FEUrea – fractional urea excretion

More reliable than FENa under diuretics: ≤ 35 % suggests prerenal kidney failure

Urine

Urine urea (or BUN) (mg/dl or mmol/l)

Enter urine and serum in the same unit: both as urea or both as BUN, both in mg/dl or both in mmol/l.

Urine creatinine

Serum

Serum urea (or BUN) (mg/dl or mmol/l)

Serum creatinine

Calculation aid for healthcare professionals: the calculator reproduces what the sources cited assign to the inputs. Clinical assessment and every treatment decision remain with the treating physician. Inputs and results are not stored.

Frequently asked questions

FEUrea – fractional urea excretion: What does this calculator compute?

Calculates the fractional excretion of urea (FEUrea = U-urea × P-creat / (P-urea × U-creat) × 100); ≤ 35 % suggests prerenal kidney failure, even under diuretic therapy (Carvounis 2002).

FEUrea – fractional urea excretion: Which sources is this calculator based on?

Carvounis CP, Nisar S, Guro-Razuman S: Significance of the fractional excretion of urea in the differential diagnosis of acute renal failure (Kidney Int 62:2223–2229) (2002)