In particular we 1) directly compared the performance of creatinine, NGAL, KIM1, L-FABP, cystatin C, and albumin in urine with their plasma counterparts (when applicable), 2) analyzed 15 additional biomarkers in plasma and in urine, 3) evaluated combinations of clinical scores and renal biomarkers for AKI risk stratification, and 4) assessed the impact of preexisting chronic kidney disease (CKD) on biomarker performance. The gene discussed is LCN2; the disease is acute kidney injury.