The Fractional Excretion of Sodium (FENa) determines if renal failure is due to pre-renal, intrinsic, or post-renal pathology.

Although often reliable at discriminating between prerenal azotemia and acute tubular necrosis, the FE Na has been reported to be <1% occasionally with oliguric and nonoliguric acute tubular necrosis, urinary tract obstruction, acute glomerulonephritis, renal allograft rejection, sepsis, and drug-related alterations in renal hemodynamics. [7]

2024年10月30日 · The fractional excretion of sodium (FENa) measures the percent of filtered sodium that is excreted in the urine. This calculation is used to help differentiate prerenal disease (decreased kidney perfusion) from acute tubular necrosis (ATN) as the cause of …

A cutoff of <1% has been used to define the sodium-avid state of prerenal azotemia, whereas a FENa >1% indicates tubular damage and intrinsic kidney injury, sometimes referred to as acute tubular necrosis.

滤过钠排泄分数 Filtration sodium excretion fraction，FENa 肾前性氮质血症1，急性肾小管坏死大于2。

钠排泄分数(fractional excretion of sodium, FENa)测量尿中排泄的钠滤过百分比。 FENa的测定结果广泛应用于鉴别急性肾损伤(acute kidney injury, AKI；以前称为急性肾衰竭)的原因是肾前性疾病(肾脏灌注下降)还是急性肾小管坏死(acute tubular necrosis, ATN)。

急性肾小管坏死时， l 肾小管吸收钠障碍， l 尿钠升高， l 因而FENa 1 也升高。 因此， l FENa 1 可作为鉴别肾前性急性肾衰和急性肾小管坏死的敏感指标。

FENa is greater than 1% and usually greater than 3% with acute tubular necrosis and severe obstruction of the urinary drainage of both kidneys. It is generally less than 1% in patients with acute glomerulonephritis, hepatorenal syndrome, and states of prerenal azotemia such as congestive heart failure or dehydration.

2023年12月31日 · Fractional excretion of sodium (FENa) is not a test. Instead it is a calculation based on the concentrations of sodium and creatinine in the blood and urine. Urine and blood chemistry tests are needed to perform this calculation.

利用U Na （20mEq/L）和FeNa（1%）來區分是renal loss還是extra-renal loss Isovolemic，水不正常滯留，但鈉總量還好故ECF沒有expansion到hypervolemic的程度。 臨床判斷相對困難，好險裡面最重要的就SIADH而已