Objectives:The role of serum cystatin C (Scys) for the detection of acute kidney injury (AKI)has not been fully discussed.This meta-analysis is aimed to comprehensively ascertain the overall diagnostic accuracy of Scys for AKI,and identify factors other than the kidney function affecting its performance.Data Sources: PubMed,Embase,Web of Science and the Cochrane Library.Study Selection: Studies diagnosing AKI across all settings using Scys in ≥30 adults of prospective cohort trials.Data Extraction:Duplicate independent review and data abstraction.Data Synthesis: A total of 30 prospective cohort studies(involving 4247 patients from 15 countries,982 patients occurring AKI) was included.Scys showed a high predictive power for all-cause AKI,that the area under the receiver operating characteristic curve was 0.89.The detailed assessment parameters,such as sensitivity,specificity,positive likelihood ratio,negative likelihood ratio and diagnostic odds ratio for Scys were 0.82,0.82,4.6,0.22and 21,respectively.However,an apparent heterogeneity (I2= 96%)has to be declared.Various Scys blood sampling point-in-time,cut-off value,and determination method resulted in various Scys predictive value for AKI.In addition,the accuracy of Scys was influenced by AKI diagnostic criteria,unacted on gender,region and age.Conclusion:Scys could be a vital promising marker to predict AKI,especially contrast-induced nephropathy.The particle-enhanced turbidimetric immunoassay method at 24-hours after the possible AKI event,referring the diagnostic criteria-50% elevated from baseline could be suggested to enhance the predictive value.