Prior evidence suggests that kidney injury molecule 1 may be able to detect kidney damage below the serum creatinine threshold7,29,30 and that patients positive for neutrophil gelatinase–associated lipocalin, even without the presence of serum creatinine criteria for AKI, were at greater risk of death and/or kidney replacement therapy.31,32 Our sensitivity analysis supported our contention that a low [TIMP-2] × [IGFBP7] cutoff (0.3 [ng/mL]2/1000) may not be useful for substaging AKI. This evidence concerns the gene IGFBP7 and acute kidney injury.