LAUSR

OBJECTIVE The optimal measuring timing of serum/plasma Cystatin C (CysC) for early detection of contrast-induced acute kidney injury (CIAKI) remains un-studied. We elucidated further on this issue. METHODS We searched PubMed, MEDLINE, and Embase from inception until March 2018 for studies evaluating diagnostic accuracy of CysC for detecting CIAKI in patients exposed to contrast agents during diagnostic examinations or cardiac/peripheral catheterizations. RESULTS A total of 10 relevant studies, comprising 2554 patients, were included and divided into the <24 -h and 24 -h groups based on CysC measuring timing (i.e., hours after contrast agent exposure). Compared with creatinine, pooled diagnostic odds ratio of CysC for detecting CIAKI of the <24 -h and 24 -h groups was 7.59 (95% confidence interval [CI]: 1.31-44.08) and 53.81 (95% CI: 13.57-213.26). Pooled sensitivity of the <24 -h and 24 -h groups was 0.81 and 0.88. Pooled specificity of the <24 -h and 24 -h groups was 0.64 and 0.88, respectively. Area under the hierarchical summary receiver operating characteristic curve of the <24 -h and 24 -h groups was 0.75 and 0.93. CONCLUSIONS Measuring CysC at 24 hours after contrast agent exposure shows higher diagnostic accuracy for early detection of CIAKI than measuring CysC at <24 hours after contrast agent exposure.