LCN2 and acute kidney injury: To analyze the discriminative power of fractional excretion of sodium and urea and of urinary NGAL to discriminate transient and intrinsic AKI, we performed receiver operating characteristic curves, yielding areas under the curves of 0.59, 0.36, and 0.67, respectively, pointing out that none of these parameters had sufficient power to discriminate intrinsic from transient AKI.