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Use this calculator to calculate the fractional excretion of urea.
About this calculator
Fractional Exceretion of Urea = Uur X Pcreat / Ucreat X Pur · 100%
Uur = Urine urea
Pcreat = Plasma creatinine
Ucreat = Urine creatinine
Pur = Plasma urea
A fractional excretion of urea of < 35% is suggestive of pre-renal azotemia. Unlike when measuring the fractional excretion of sodium, FEUrea can be used even when patients are taking diuretics._
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(6):2223-2229. (2002)
QxMD Nephrology contributing author: Daniel Schwartz, MD, FRCP(C)