FEUrea Calculator
Calculate Fractional Excretion of Urea (FEUrea %) using serum urea, urine urea, serum creatinine, and urine creatinine. This calculator provides supportive information during the evaluation of acute kidney injury.
Calculation Result
Formula
Interpretation
| FEUrea (%) | General Interpretation |
|---|---|
| <35% | Suggestive of Prerenal Acute Kidney Injury |
| 35–50% | Intermediate / Indeterminate |
| >50% | Suggestive of Intrinsic Renal Acute Kidney Injury |
Clinical Use
Fractional Excretion of Urea (FEUrea) is a calculated laboratory parameter used as an adjunct in the evaluation of acute kidney injury. It may provide additional information when assessment of urinary sodium excretion is affected by diuretic therapy.
FEUrea should not be interpreted in isolation. Volume status, medications, urine findings, renal function, and other clinical and laboratory information should also be considered.
Frequently Asked Questions
What is FEUrea?
FEUrea stands for Fractional Excretion of Urea. It estimates the percentage of filtered urea that is excreted in the urine.
When is FEUrea useful?
FEUrea may be useful during the evaluation of acute kidney injury, particularly when diuretic therapy may make FENa less reliable.
What does a FEUrea below 35% suggest?
A FEUrea below 35% may be consistent with prerenal acute kidney injury, particularly when reduced renal perfusion is present.
What does a FEUrea above 50% suggest?
A FEUrea above 50% may suggest intrinsic renal injury. Clinical correlation is required.
Can FEUrea diagnose kidney disease?
No. FEUrea is a supportive laboratory calculation and should not be used as the sole basis for diagnosing kidney disease or determining the cause of acute kidney injury.
Clinical Applications
- Evaluation of acute kidney injury (AKI)
- Assessment of prerenal kidney dysfunction
- Evaluation of intrinsic renal injury
- Assessment of renal urea handling
- Supportive evaluation when diuretics may affect FENa
Disclaimer
This calculator is intended for educational and laboratory reference purposes only. It should not replace professional medical advice, diagnosis, treatment, or institutional protocols. FEUrea results should always be interpreted in the context of the complete clinical picture.
References
- Carvounis CP, Nisar S, Guro-Razuman S. Significance of the Fractional Excretion of Urea in the Differential Diagnosis of Acute Renal Failure. Kidney International. 2002.
- KDIGO Clinical Practice Guideline for Acute Kidney Injury.
- Tietz Fundamentals of Clinical Chemistry and Molecular Diagnostics.
