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AKI Staging (KDIGO)Anion Gap + Delta-Delta CKD Stage (KDIGO)Creatinine Clearance Electrolyte & Free Water FENa FEUrea KFRE — Kidney Failure Risk Kt/V Dialysis Sodium Correction UACR UPCR Urea Reduction Ratio (URR) Calculator Uric Acid & FEUA Urinary Anion Gap Winter's Formula eGFR (CKD-EPI)

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Recent Journal Updates

Alzheimers & DementiaJun 8, 2026

Differential associations of plasma biomarkers with Alzheimer's disease and small vessel disease: A multimodal imaging study

Clinical Context

We think this has broad domain relevance to FEUrea — Fractional Excretion of Urea.

WHO NewsMay 20, 2026

Seventy-ninth World Health Assembly honours global champions advancing primary health care

Clinical Context

We think this might be relevant to the clinical guidance for FEUrea — Fractional Excretion of Urea.

WHO NewsMay 18, 2026

Director-General presents Award for Global Health to four distinguished leaders

Clinical Context

We think this might be relevant to the clinical guidance for FEUrea — Fractional Excretion of Urea.

FEUrea

FEUrea Calc

Fractional Excretion of Urea

Plasma Values

BUN/Urea (PUrea) mg/dL

Creatinine (PCr) mg/dL

Urine Values

Urea (UUrea) mg/dL

Creatinine (UCr) mg/dL

Superior to FENa in patients treated with diuretics.

The Urea Ratio

Enter paired plasma and urine urea chemistries to differentiate kidney injury types.

Guidelines & Evidence

Verified

Last Review: 2026

When to Use

When to Use

AKI differential (Prerenal vs. ATN) in patients who have received loop or thiazide diuretics within 24 hours.

Cases where FENa is unreliable: diuretics, contrast nephropathy, pigment nephropathy, early ATN.

Non-oliguric AKI where FENa accuracy is reduced.

Suspicion of Hepatorenal Syndrome (HRS) — FEUrea is typically very low.

Key Advantage Over FENa

Diuretics block Na reabsorption in the loop of Henle, falsely elevating FENa above 1% even in pure prerenal states. Urea reabsorption is not affected by diuretics, making FEUrea a more reliable marker when diuretic therapy is active.

Related Scores in Practice

In clinical practice, this assessment is frequently evaluated alongside other validated measures. Depending on the patient's presentation and specific diagnostic requirements, you may also need to utilize the FENa, AKI Staging (KDIGO) or the Urinary Anion Gap to formulate a comprehensive care plan.

Last Comprehensive Review: 2026

Related Nephrology Tools

Urinary Anion Gap

Anion Gap + Delta-Delta

Uric Acid & FEUA

Winter's Formula

Sodium Correction

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