Many novel biomarkers have been investigated in AKI, either serum or urine (cystatin-C, Il-18, KIM-1, NGAL). Results have been varied, with potential problems being lack of specificity to AKI, cost and the heterogeneous nature of patient populations in the various studies. NGAL has emerged as potentially the most specific to early AKI and additionally a number of commercially available assays are now available. Interest has been shown in the use of biomarker panels, allowing for improved sensitivity, albeit at a higher cost. Urinary proteomic analysis has been used as an investigative technique for AKI for the last ten years, but diverse populations and lack of blinding hampered early studies. A recent paper used techniques developed by collaborators on this proposal to improve the performance of proteomic assays, with impressive performance of these assays when looking at critically ill patients with AKI.