Nonoliguric acute renal failure associated with a low fractional excretion of sodium.

Measurement of the fractional excretion of sodium has been recommended as a useful clinical tool in evaluating acute renal failure. Six patients with nonoliguric acute renal failure had a fractional excretion of sodium less than or equal to 1.0%; these patients had severe liver dysfunction, which suggested a sodium-avid state. A review of the literature showed that in patients with other sodium-avid states (congestive heart failure, nephrotic syndrome, and burns) the fractional excretion of sodium was frequently less than or equal to 1.0%. The fractional excretion of sodium is thus a less useful diagnostic test in patients whose clinical state makes them sodium avid.