Abstract: Ｏｂｊｅｃｔｉｖｅ：To investigate the diagnosis of serine protease inhibitor A3 (SerpinA3) in acute kidney injury (AKI) and its prognostic value.
Ｍｅｔｈｏｄｏｌｏｇｙ：Ninety-three patients with AKI admitted to the ICU of Guangdong Provincial Peoples Hospital (AKI group) and 89 patients with non-AKI in the ICU during the same period (control group) were prospectively included. and blood SerpinA3 and urine SerpinA3 were detected by ELISA. Clinical data of the patients and the data of the laboratory tests were collected. The correlation between blood SerpinA3, urine SerpinA3, and clinical indexes was analyzed by Spearmans method, and the independent risk factors for the occurrence of AKI were analyzed by binary logistic regression. Patients with AKI were followed up for 28 days, and those who survived and died at 28 days were analyzed using the subject's working curve (ROC) and the survival curve of patients with AKI.
Ｒｅｓｕｌｔｓ：Blood and urinary SerpinA3 levels, urinary SerpinA3 levels in AKI patients were ［158250 (107025, 259575) ng／mL and 1618 (678.8, 5496) ng／mL, respectively; blood and urinary SerpinA3 in non-AKI patients were more than 125850 (80775, 196575), respectively; 1618 (678.8, 5496) ng／mL than 345.0 (173.8, 675.0) ng／mL, AKI patients blood and urinary SerpinA3 were more than both P<0.05］ significantly higher than that of the non-AKI group, and both P<0.05.; Spearman correlation analysis showed a positive correlation between urinary SerpinA3 and blood creatinine (r=0.213, P<0.05). The area under the ROC curve for patients with AKI diagnosed by blood SerpinA3 and urine SerpinA3 was 0.606 and 0.885; respectively. The area under the ROC curve for urinary SerpinA3 in predicting intra-28-day morbidity and mortality in patients with AKI was 0.8, with a sensitivity and specificity of 72.73％ and 77.24％, respectively. The results of the Kaplan-Meier survival curve analysis showed that patients who had urinary SerpinA3>5496 ng／mL at the time of the occurrence of AKI had a significantly lower survival rate within 28 days and a poorer prognosis.
Ｃｏｎｃｌｕｓｉｏｎ：Urinary SerpinA3 is valuable as a biological marker for the diagnosis of AKI and for predicting the prognosis of patients with AKI.

Key words: acute kidney injury, SerpinA3, prognosis