Calc Function

    • Calcs that help predict probability of a diseaseDiagnosis
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    Patent Pending

    Fractional Excretion of Urea (FEUrea)

    Determines the cause of renal failure. Similar to the FENa, but can be used on patients on diuretics.
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    Pearls/Pitfalls

    While lesser known than FENa, the FEUrea can be used in patients on diuretics, since urea excretion is not significantly affected by diuretics.

    mg/dL
    mg/dL
    mg/dL
    mg/dL

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    Next Steps
    Evidence
    Creator Insights

    Advice

    Some experts recommend placing a foley catheter in all patients with acute renal failure to remove obstructive uropathy from the differential. This can be considered, especially in patients who are unable to provide information about their bladder and urination (or when ultrasound is unavailable).

    Formula

    Fractional Excretion of Urea (FEUrea) = (SerumCr * UUrea) / (SerumUrea x UCr) %

    Facts & Figures

    This test can provide similar information to the FENa equation, but can still be used in patients on diuretic therapy (diuretics alter the sodium concentration, making the FENa equation unusable).

    Prerenal Intrinsic Renal Postrenal
    FENa <1% >1% >4%
    FEUrea ≤ 35% >50% N/A
    Dr. Christos Carvounis

    About the Creator

    Christos Carvounis MD, is an internist working at the Department of Internal Medicine, Kyanous Stavros Medical Center in Greece. He previously conducted research at at Nassau University Medical Center in the nephrology department.

    To view Dr. Christos Carvounis's publications, visit PubMed