CST3 and acute kidney injury: In a pool analysis of four studies that used urinary creatinine-adjusted data [116, 130, 148, 149], the sensitivity for the early diagnostic capacity of urinary cystatin C was 0.52, the specificity was 0.70, and the AUC was 0.64 (95% confidence interval 0.62–0.66); therefore, the diagnostic accuracy was low, indicating that the urinary cystatin C is of limited utility for the early diagnosis of AKI.