cliot (version 1.0.0)

calculate_fena: Fractional Excretion of Sodium (FENa)

Description

Calculates the Fractional Excretion of Sodium (FENa) to help differentiate between prerenal azotemia and acute tubular necrosis (ATN) in patients with oliguric acute kidney injury.

Usage

calculate_fena(serum_sodium, serum_creatinine, urine_sodium, urine_creatinine)

Value

A list containing:

FENa_Percent

The calculated FENa percentage.

Etiology

Interpretation (Prerenal < 1%, Intrinsic > 2%).

Arguments

serum_sodium

Numeric. Serum Sodium level in mEq/L or mmol/L.

serum_creatinine

Numeric. Serum Creatinine level in mg/dL or umol/L (must use consistent units with urine creatinine).

urine_sodium

Numeric. Urine Sodium level in mEq/L or mmol/L.

urine_creatinine

Numeric. Urine Creatinine level in mg/dL or umol/L (must use consistent units with serum creatinine).

References

Espinel CH. The FeNa test. Use in the differential diagnosis of acute renal failure. JAMA. 1976;236(16):1795-1797. doi:10.1001/jama.1976.03270170035022

Examples

# Example 1: Prerenal (Dehydration)
# SNa 140, SCr 1.5, UNa 10, UCr 100
# FENa = (10 * 1.5) / (140 * 100) * 100 = 0.11%
calculate_fena(140, 1.5, 10, 100)

# Example 2: Intrinsic (ATN)
# SNa 135, SCr 2.0, UNa 40, UCr 40
# FENa = (40 * 2.0) / (135 * 40) * 100 = 1.48% (Indeterminate range, close to ATN)
calculate_fena(135, 2.0, 40, 40)