In recent years, a new AKI biomarker system, a composite of the two independent proteins metalloproteinase inhibitor 2 (TIMP2) and the IGF-binding protein 7 (IGFBP7), in urine samples has been introduced and has been widely accepted on the basis of a large number of clinical trials [9,22,23]. The gene discussed is IGFBP7; the disease is acute kidney injury.