Fractional Excretion of Sodium: Sensitivity and Specificity
Fractional excretion of sodium: (urine Na / urine Cr) / (plasma Na / plasma Cr). In the context of acute renal failure, generally <1% is indicative of prerenal causes while >2% is indicative of ATN.
37% sensitive, 95% specific
76.6% sensitive, 96% specific
68% sensitive, 100% specific