AQP2 and acute kidney injury: Receiver operating characteristic (ROC) curves showed that principal cell-specific AQP2 abundance in uEVs predicted acute kidney injury (antibody 19-64-17; area under curve 0.71; 95% confidence interval 0.60 to 0.83; p = 0.001; Figure 5B; and antibody 19-65-1; area under curve 0.70; 95% confidence interval 0.58 to 0.82; p = 0.003; Figure 5C).