The most effective timepoint for distinguishing between AKI and no AKI based on urinary collectrin was on POD 1 with a significant difference in collectrin levels of 2190 ± 3728 pg/mL in AKI patients and 3768 ± 3435 pg/mL in non-AKI patients (p = 0.01) (Figure 2). Here, CLTRN is linked to acute kidney injury.