FENa & Urine Indices Calculator

Fractional excretion of sodium, urine anion gap, and renal failure index for AKI workup.

Medical Disclaimer

This calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about your health. Never disregard professional medical advice or delay seeking it because of results from this tool.

Inputs

Urine Sodium (mEq/L)

Plasma Sodium (mEq/L)

Urine Creatinine (mg/dL)

Plasma Creatinine (mg/dL)

Urine Potassium (mEq/L)

Urine Chloride (mEq/L)

Tab to move between fields

Results

FENa

0.43%

Urine Anion Gap20 mEq/L

Renal Failure Index0.6

UCr/PCr Ratio66.7

How to Use This Calculator

Enter spot urine and plasma sodium (mEq/L) and creatinine (mg/dL) values.
Enter spot urine potassium (mEq/L) and chloride (mEq/L) for the urine anion gap.
Read the FENa (%): values <1% suggest pre-renal, 1-2% mixed, >2% intrinsic renal disease.
Review the urine anion gap: negative values suggest GI bicarbonate loss, positive values suggest renal tubular acidosis.
Use the renal failure index and UCr/PCr ratio to further differentiate acute kidney injury etiology.

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