Lab

Fractional Excretion of Urea

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Fractional Excretion of Urea, FEUrea

  • See Also
  1. Acute Kidney Injury
  2. Fractional Excretion of Sodium (FENa)
  • Indications
  1. Acute Kidney Injury
    1. Distinguishes Prerenal Failure from instrinsic Renal Failure (e.g. Acute Tubular Necrosis)
    2. Alternative to Fractional Excretion of Sodium (FENa) as it is not altered by Diuretic use
  • Calculation
  1. Fractional Excretion of Urea (FEUrea in percent) = (sCr * uUrea) / (sUrea x uCr) * 100
  2. Where
    1. sCr: Serum Creatinine
    2. uCr: Urine Creatinine
    3. sUrea: Serum Urea (Blood Urea Nitrogen)
    4. uUrea: Urine Urea
  • Interpretation
  • Fractional Excretion of Urea (FEUrea)
  1. FEUrea <35%: Prerenal Failure
  2. FEUrea >50%: Intrinsic renal disease (e.g. Acute Tubular Necrosis)
  • References
  1. Carvounis (2002) Kidney Int 62: 2223-9 [PubMed]