Abstract: Objective  To explore the application value of urinary calprotectin in adult acute kidney injury (AKI) by observing urinary calprotectin concentration in adult AKI patients and healthy people.  Methods  Fifty patients with AKI (AKI group) and 30 healthy people (healthy control group) were selected to determine the indexes of urinary calprotectin, serum creatinine, blood urea nitrogen, urinary kidney injury molecule-1 (KIM-1), blood albumin and hemoglobin. General clinical data and laboratory indexes were compared between the two groups. ROC curve was used to analyze the predictive value of urinary calprotectin for adult AKI.  Results  Urinary calprotectin, urinary KIM-1, serum creatinine and blood urea nitrogen were higher in AKI group than in healthy control group (t=10.113, 9.152, 11.119 and 9.049 respectively; P＜0.001). Urinary calprotectin was positively correlated with serum creatinine (r=0.794, P＜0.001), urea nitrogen (r=0.462, P=0.001) and urinary KIM-1 (r=0.409, P=0.003), and was negatively correlated with serum albumin (r=-0.620, P=0.042) and hemoglobin (r=-0.289, P＜0.001) in AKI group. When the diagnostic limit of urinary calprotectin for adult AKI was set at 55.17ng/ml, the area under the ROC curve was 0.747 (95% CI: 0. 641～0.853), with the sensitivity of 62.0% and specificity of 90.0%.  Conclusion  Urinary calprotectin concentration was significantly increased, and was positively correlated with serum creatinine, blood urea nitrogen and urinary KIM-1 levels in adult AKI patients. The sensitivity and specificity of urinary calprotectin for the diagnosis of adult AKI are higher. Therefore, urinary calprotectin has an important clinical value in the prediction and evaluation of therapeutic effect and recovery process in adult AKI patients.

Key words: Acute renal injury, Urinary calprotectin, Early prediction, Recovery process