IGFBP7 and acute kidney injury: While some investigators demonstrated that urinary [TIMP-2] × [IGFBP-7] was a sensitive and specific early biomarker in identifying AKI following cardiac surgery [18, 21], Wetz et al. reported that urinary [TIMP-2] × [IGFBP-7] could not discriminate patients with a KDIGO score of 0 from those with a KDIGO score of 1 or 2 [27].