CST3 and acute kidney injury: The product of urinary TIMP-2 and IGFBP7, [TIMP-2] × [IGFBP7], has previously been identified as a predictor for stage 2 or 3 AKI, performing better than urinary NGAL, KIM-1, plasma Cystatin C or urinary TIMP-2 and IGFBP7 alone11,18,19.