Clinlab Navigator

Fractional Excretion Of Urea

Fractional excretion of sodium and urine sodium concentration are difficult to interpret in patients treated with diuretics, because the ensuing natriuresis raises FENa, even in patients with prerenal disease.

In patients treated with diuretics, calculating the fractional excretion of urea (FEurea) may be helpful, because urea is primarily absorbed in the proximal tubule.

The accuracy of FEurea depends on intact proximal function because fractional excretion of urea increases when proximal reabsorption is reduced.

Typically, FEurea is 50 to 65% in ATN and below 35% in prerenal disease. Although still controversial, the preponderance of the evidence suggests that FEurea is more accurate than FENa in patients receiving diuretics.

AddThis Social Bookmark Button