FEUrea (Fractional Excretion of Urea) Diuretic-Adjusted AKI Calculator

Evaluate AKI in patients on diuretics via FEUrea = (U_Urea × P_Cr) / (BUN × U_Cr) × 100.

Fractional Excretion of Urea (FEUrea)
20 %
Serum BUN : Creatinine Ratio 20 : 1
Urine-to-Plasma Urea Ratio 9.05 : 1
Urine-to-Plasma Creatinine Ratio 45.24 : 1
Inputs
⚡ Scenarios:
mg/dL
Serum Blood Urea Nitrogen (BUN) in mg/dL.
mg/dL
Serum Creatinine in mg/dL.
mg/dL
Spot Urine Urea Nitrogen in mg/dL.
mg/dL
Spot Urine Creatinine in mg/dL.
Results & Graph
Fractional Excretion of Urea (FEUrea)
20 %
Serum BUN : Creatinine Ratio
20 : 1
Urine-to-Plasma Urea Ratio
9.05 : 1
Urine-to-Plasma Creatinine Ratio
45.24 : 1

Fractional Excretion of Urea (FEUrea)

Graph 1 • FEUrea Kidney Fraction • Domain Architecture & Live Telemetry Maps Serum Bun Mg Dl, Serum Creatinine Mg Dl, Urine Urea Nitrogen Mg Dl through FEUrea Kidney Fraction Formula.
FEUrea Kidney Fraction • Clinical & Physiological Reference Scale Low / Baseline Target / Reference Elevated / Watch High / Action Fractional Excretion of Urea (FEUrea): 20 % Serum BUN : Creatinine Rat 20 : 1 Urine-to-Plasma Urea Ratio 9.05 : 1 Urine-to-Plasma Creatinine 45.24 : 1
Graph 2 • Fractional Excretion of Urea (FEUrea) Across Serum Bun Mg Dl Sweep (40% → 160%) Evaluates FEUrea (%) = [ (Urine_Urea × Serum_Cr) / (Serum_BUN × Urine_Cr) ] × 100 across 7 operating points (current input highlighted).
0 % 27.50 % 55.00 % 50 16.80mg/dL 33.33 25.20mg/dL 25 33.60mg/dL 20 42mg/dL 16.67 50.40mg/dL 14.29 58.80mg/dL 12.50 67.20mg/dL
Graph 3 • Joint Sensitivity: Serum Bun Mg Dl × Serum Creatinine Mg Dl Compares Fractional Excretion of Urea (FEUrea) when Serum Creatinine Mg Dl is shifted +25% (solid) vs. −25% (dashed).
0 % 19.64 % 39.28 % --- Serum Creatinine Mg Dl @ 75% 35.71 -30% 29.41 -15% 25 +0% 21.74 +15% 19.23 +30%
Summary: FEUrea is 20% (Pre-Renal AKI (≤35%)) and Serum BUN:Cr ratio is 20:1.
Summary: FEUrea is 20% (Pre-Renal AKI (≤35%)) and Serum BUN:Cr ratio is 20:1.
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Formula & Mathematical Methodology: FEUrea Kidney Fraction Formula

FEUrea (%) = [ UrineUrea × SerumCrSerumBUN × UrineCr ] × 100
FEUrea (%) = [ (Urine_Urea × Serum_Cr) / (Serum_BUN × Urine_Cr) ] × 100
  • serumBunMgDl: Serum Bun Mg Dl (mg/dL)
  • serumCreatinineMgDl: Serum Creatinine Mg Dl (mg/dL)
  • urineUreaNitrogenMgDl: Urine Urea Nitrogen Mg Dl (mg/dL)
  • urineCreatinineMgDl: Urine Creatinine Mg Dl (mg/dL)

Rounding: Clinical scores round to statutory integer or decimal precision; physiological metrics round to 2 decimal places.

Worked Example: Clinical / Physiology Scenario: FEUrea Kidney Fraction

Evaluate AKI in patients on diuretics via FEUrea = (U_Urea × P_Cr) / (BUN × U_Cr) × 100.

  1. Enter lab values, anthropometric measurements, or performance test metrics.
  2. Evaluate the reference equation: FEUrea (%) = [ (Urine_Urea × Serum_Cr) / (Serum_BUN × Urine_Cr) ] × 100.
  3. Inspect the primary classification, supporting indices, and 3 SVG charts.
Result: Computes FEUrea Kidney Fraction via FEUrea (%) = [ (Urine_Urea × Serum_Cr) / (Serum_BUN × Urine_Cr) ] × 100.

Frequently Asked Questions

How does the FEUrea (Fractional Excretion of Urea) Diuretic-Adjusted AKI Calculator compute its result?

It evaluates FEUrea (%) = [ (Urine_Urea × Serum_Cr) / (Serum_BUN × Urine_Cr) ] × 100 directly in your browser and updates three custom SVG visualizations in real time.

Can I use Goal Seek to solve backwards for a target lab value or pace?

Yes. Click "🎯 Goal Seek" in the results toolbar to solve backwards for any numeric input parameter.

Are my health and biometric inputs kept private?

Yes. All calculations run 100% locally on your device with zero external transmission.

Health & Fitness · Clinical Nephrology & Electrolytes

FEUrea (Fractional Excretion of Urea) Diuretic-Adjusted AKI Calculator: inputs, method, and how to read the result

Evaluate AKI in patients on diuretics via FEUrea = (U_Urea × P_Cr) / (BUN × U_Cr) × 100.

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

  • Serum Bun Mg Dl: Serum Blood Urea Nitrogen (BUN) in mg/dL.
  • Serum Creatinine Mg Dl: Serum Creatinine in mg/dL.
  • Urine Urea Nitrogen Mg Dl: Spot Urine Urea Nitrogen in mg/dL.
  • Urine Creatinine Mg Dl: Spot Urine Creatinine in mg/dL.

What the calculation includes

With the default values shown, Fractional Excretion of Urea (FEUrea) is 20 %. The calculation follows FEUrea Kidney Fraction Formula; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Serum Bun Mg Dl from 42 mg/dL to 46 mg/dL changes Fractional Excretion of Urea (FEUrea) from 20 % to 18.26 %. This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

  • Uses peer-reviewed clinical and sports physiology formulas.
  • For educational and informational reference only; clinical scores do not replace physician judgment or laboratory reference ranges.

Scope: Global Clinical & Sports Science Consensus Check the assumptions and limitations against your situation before relying on the estimate.

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