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fractional-excretion

Fractional Excretion of Na calculator

Fractional Excretion of Na calculator is to measure of the percentage of sodium excreted in the urine versus the sodium reabsorbed by the kidney.FENa is not a test, but rather a calculation based on the concentrations of sodium and creatinine in your blood and urine.


Calculation of Fractional Sodium Excretion

Urine Na  
Urine Cr  
Serum Na  
Serum Cr  
FENa=

 
   
  



Formulas Used:

Fractional Excretion of Na ( FENa) in %=[ (urine Na) / (serum Na) ] x 100 / [ (urine Cr) / (serum Cr) ]

To accurately interpret FENa, patients should not have recently received diuretics. 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. FENa may also be less than 1% with acute partial urinary tract obstruction Free online Medical Calculators.