LCN2 and acute kidney injury: However, CART analysis revealed that the best predictor of newly developed AKI was urinary L-FABP in patients without hyperlactatemia, i.e. those with blood lactate ≤2 mmol/L, whereas the best predictor for patients with hyperlactatemia, i.e. those with blood lactate >2 mmol/L, was urinary NGAL (Fig. 3).