Objective:To investigate the kidney injury in the patients after contrast examination. Methods:34 patients underwent CT enhancement scanning or intravenous pyelography were enrolled in this study. The concentration of Scr and urine NGAL at different time points were measured. Results:None of contrast-induced nephropathy(CIN) occurred in 34 enrolled patients. After the contrast examination,Scr did not significantly change at any time point but urine NGAL significantly elevated at 2 h and 8 h. Conclusion:Early kidney injury occurred in the patients after the contrast examination without the change of Scr level.