苦味酸法和酶法检测肌酐对肾小球滤过率预测公式效能的影响

Impacts of different creatinine detection methods on the efficacy of different GFR estimation equations

目的 探讨应用苦味酸法和酶法检测肌酐对GFR评估方程适用性的影响.方法 选取2007-2009年华北（北京）、东北（大连）、华东（上海）、华中（长沙）4个区域三级甲等综合医院CKD患者176例.以双血浆法99m Tc-二乙三胺五乙酸（99mTc-DTPA）血浆清除率作为176例CKD患者的rGFR.使用4个不同厂家的酶法或苦味酸法肌酐试剂配套不同厂家自动生化分析仪分别测定患者血肌酐,同时应用体表面积（ BSA）标化的Cockcroft-Gault方程（CG/BSA方程）、简化MDRD方程、校正至同位素稀释质谱法的简化MDRD方程（MDRD-IDMS方程）、CKD流行病学合作研究方程（CKD-EPI方程）及2个国内简化MDRD改良方程（课题组方程1、2）分别计算eGFR,比较不同估算结果与rGFR的相关性、偏差、精密度以及30％准确性.结果 176例CKD患者的rGFR为[40.70（19.41～84.35）] ml·min-1·（1.73 m2）-1.应用苦味酸法测定肌酐时,各方程评估的eGFR与rGFR的ICC在0.879～0.923之间；应用酶法测定肌酐时,各方程评估的eGFR与rGFR的ICC在0.925 ～0.946之间,相关性优于应用苦味酸法测定肌酐.Bland-Altman图显示,各方程评估的eGFR在高值区偏差较大,但用酶法时偏离程度均小于应用苦味酸法.在rGFR≥60 ml·min-1·（1.73 m2）-1时,各方程应用酶法测定肌酐时的30％准确性在68.3％～90.0％之间,应用苦味酸法30％准确性在41％～75％之间,除课题组方程1外,其他方程应用酶法测定肌酐时的准确性均显著高于苦味酸法.而rGFR＜60ml· min-1·（1.73 m2）-1时,应用酶法、苦味酸法测定肌酐的30％准确性分别在39.7％～49.1％、40.5％～52.6％之间.对于同一方程,应用酶法测定肌酐的两套不同检测系统间,其30％准确性差异无统计学意义,而应用苦味酸法的两套不同检测系统间,其30％准确性差异有统计学意义.结论 同一评估方程使用苦味酸法和酶法两种不同的肌酐检测方法时,结果存在显著性差异.采用酶法测定肌酐时,方程评估的eGFR结果在相关性、偏离程度、准确性方面均优于苦味酸法.

Objective To investigate the impacts of different serum creatinine detection methods,including Jaffe and enzymatic methods,on the efficacy of different GFR estimation equations in CKD patients in China.Methods rGFR of 176 patients with CKD were determined by dual plasma sample method 99mTc-diethylenetriamine pentaacetic acid （99mTc-DTPA） plasma clearance rate.Serum creatinine was detected with four kinds of creatinine reagents from different manufacturers.Cockcroft-Gault Equation corrected for body surface area （CG/BSA）,simplified Modification of Diet in Renal Disease （MDRD） Study equation,IDMS-traceable MDRD equation,CKD epidemiology collaborative research （CKD-EPI） equation and two Chinese simplified MDRD equation （project group equation 1,2） were applied to calculate estimated GFR （eGFR）respectively.eGFR were compared with rGFR for the correlation, deviation, precision and 30% accuracy.Results The mean rGFR of 176 patients with CKD,was [ 40.70 （ 19.41 -84.35 ） ] ml · min- 1 ·（ 1.73 m2 ） -1.For all GFR estimation equations,there were significant differences in eGFR results between enzymatic method and Jaffe method,when analyzed by the Wilcoxon signed-rank test.eGFR results assessed by two enzymatic creatinine detection systems showed no significant difference,while eGFR results analyzed by two Jaffe detection system were significantly different.The intraclass correlation coefficient （ICC） of eGFR and rGFR ranged from 0.879 to 0.923 by Jaffe method,while from 0.925 to 0.946 by enzymatic creatinine method.ICC and Pearson correlation analysis revealed a significant correlation between eGFR and rGFR,and the correlation was better when using enzymatic method.Bland-Altman plots indicated that large deviation occurred in the high value area of GFR using various equations.However,deviation with the enzymatic creatinine method was smaller than that with the Jaffe method. When rGFR ≥ 60 ml · min- 1 ·（1.73 m2） -1,the 30% accuracy of eGFR using enzymatic creatinine method for all six equations was between 68.3% and 90.0%,while it was between 41% and 75% when using Jaffe method. The 30% accuracy of eGFR using enzymatic creatinine method was significantly higher than that using picric acid method for these equations except for the project group equation 1.When rGFR 〈60 ml · min -1 · （ 1.73 m2 ） -1,the 30% accuracy of eGFR using both methods was between 39.7% -49.1%,40.5% -52.6%respectively,and the difference of data showed no statistical significance.For the same equation,there was a significant differernce in 30% accuracy of eGFR between two enzymatic creatinine detection systems,while there was no significant differernce between two Jaffe creatinine detection systems.Conclusions A significant difference was demonstrated in the same GFR evaluation equation using two different creatinine detection methods （Jaffe method and enzymatic method）.The correlation between rGFR and eGFR,the degree of deviation,and accuracy of eGFR results assessed by enzymatic creatinine method were better than those by Jaffe method.The eGFR results assessed by different enzymatic detection systems revealed no significant difference.