RESEARCH ARTICLE Comparison of Plasma and Urine Biomarker Performance in Acute Kidney Injury

Background New renal biomarkers measured in urine promise to increase specificity for risk stratification and early diagnosis of acute kidney injury (AKI) but concomitantly may be altered by urine concentration effects and chronic renal insufficiency. This study therefore directly compared the performance of AKI biomarkers in urine and plasma. Methods This single-center, prospective cohort study included 110 unselected adults undergoing cardiac surgery with cardiopulmonary bypass between 2009 and 2010. Plasma and/or urine concentrations of creatinine, cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), liver fatty acid-binding protein (L-FABP), kidney injury molecule 1 (KIM1), and albu-min as well as 15 additional biomarkers in plasma and urine were measured during the peri-operative period. The primary outcome was AKI defined by AKIN serum creatinine criteria within 72 hours after surgery. Result