The FENa test. Use in the differential diagnosis of acute renal failure
C. H. Espinel
The FENa test, a determination of the excreted fraction of the filtered
sodium, was performed in patients in the oliguric phase of acute renal
failure. Patients with prerenal azotemia had an FENa of less than 1, and
patients with acute tubular necrosis had an FENa of more than 3 (P less
than .001). This simple test clearly differentiates between these two
conditions and, thus, is of considerable clinical value.