With great interest, we read the recent original article written by Zihan Chang et al1 , which was published in European Journal of Neurology. In this multicenter retrospective case-control study, the authors found that elevated serum Cystatin C may be associated with unfavorable clinical outcomes after intravenous tissue plasminogen activator therapy, independently. The results of receiver operating characteristic curves also showed that model 1 (combining baseline Cystatin C, hypertension, early infarct signs on admission CT scan, WBC and smoking) was able to predict good&sustained benefit (Area under the curve is 0.75). What is more, model 2 (combining baseline Cystatin C, NIHSS on admission, hypertension, early infarct signs on admission CT, and TOAST subtype large-artery atherosclerosis) can be used to forecast good functional outcome (Area under the curve is 0.86). Nevertheless, I still have comments.