In recent studies, the most promising early noninvasive AKI biomarkers were serum cystatin C (CysC), urinary interleukin-18 (IL-18), serum and urinary neutrophil gelatinase-associated lipocalin (N-GAL), kidney molecule-1 (KIM-1), osteopontin (OPN), and beta-2 microglobulin (B2mG)—Table 2 [39]. This evidence concerns the gene SPP1 and acute kidney injury.