血清胱抑素C对肾功能损伤的评估

Estimation of serum cystatin C on renal dysfunction

目的探讨血清胱抑素C（SCys C）在肾脏功能损伤筛查、诊断中的应用价值。方法采用胶体金免疫比浊法检测SCys C，对126例健康体检者、89例尿微量白蛋白（MA）〉30mg／gCr患者和12例肾移植患者分别根据Cockroft—Gault公式、MDRD7公式、AASK公式、Nankivell公式和Schwartz公式估算肌酐清除率（eCCr）和／或肾小球滤过率（eGFR），并对计算所得eGFR及eCCr与SCys C作相关性分析，并计算SCysC的受试者操作特征（ROC）曲线下面积。结果SCys C与Cockroft—Gault公式、MDRD7公式、AASK公式、Nankivell公式和Schwartz公式的相关系数分别为：-0．599、-0．654、-0．663、0．735和-0．701（n=227），P〈0．001，呈强负相关；在eGFR〉80mL／min、尿白蛋白／肌酐≥30mg／gCr时SCysC的ROC曲线下面积分别为0．775、0．803、0．799、0．763和0．819，P〈0．05。结论在肾脏的代偿能力尚能维持正常肾小球滤过功能时，SCys C不会明显升高，SCys C作为终末期肾病的早期诊断指标，比血清肌酐更敏感，但对于早期肾功能损伤的诊断，尿自蛋白比SCys C敏感；肾移植患者SCys C浓度明显高于健康对照者，但不能用于评估肾小球滤过功能。只有在尿白蛋白阳性情况下，用于监控肾脏损伤的进程，SCys C比血清肌酐更有价值。

Objective To explore the value of serum cystatin C （SCys C） in the screening and diagnosis of renal dysfunction. Methods 126 healthy subjects, 89 patients with a high urinary microalbumin（MA） level （〉30 mg/gCr） and 12 patients with renal transplantation were enrolled in the study. Colloidal gold immunoturbidimetry was applied to detecting SCys C. Estimated creatinine clearance （eCCr） and/or estimated glomerular filtration rate （eGFR） were acquired by Cockroft-Gault formula, MDRD7 formula, AASK formula, Nankivell formula and Schwartz formula. Correlative analysis was performed on eGFR, eCCr and SCys C. The area under the receiver operating characteristic （ROC） curve was calculated. Results The correlation coefficient between SCys C and Cockroft-Gault, MDRD7, AASK, Nankivell, and Schwartz was -0. 599,-0. 654,-0. 663,-0. 735 and -0. 701（n =227）respectively. There existed a strong negative correlation （P〈0. 001）. In the case of eGFR〉80 mL/min and urinary albumin/creatinine≥30 mg/gCr, the area under ROC curve was 0. 775, 0. 803, 0. 799, 0. 763 and 0. 819 respectively （P〈0.05）. Conclusion SCys C doesn＇t increase significantly when renal compensatory ability is enough to maintain normal glomerular filtration function. As an early diagnostic indicator of end-stage renal disease, SCys C is more sensitive than serum creatinine, while urinary albumin is more sensitive than SCys C in the diagnosis of early renal dysfunction. Since SCys C of patients undergoing renal transplantation is significantly higher than that of normal controls, it can＇t be used to evaluate the glomerular filtration function, Only when urine albumin is positive, is SCys C more valuable than creatinine in the process of monitoring renal injury.