血清尿酸参考测量程序的优化及其在常规系统中的应用

Optimization of serum uric acid reference measurement proceduce and application in conventional systems

目的优化血清尿酸参考测量程序(简称参考方法),为尿酸常规测量系统的建立提供参考。方法建立美国临床化学协会(AACC)推荐的血清尿酸参考方法,并进行优化(离心40 min后再次离心15 min),采用美国国家标准和技术研究院(NIST)标准品SRM 909C和国际比对样本RELA20B、RELA21A进行正确度验证。通过高、中、低值临床剩余血清样本验证精密度。配置6个浓度梯度进行线性评估。采用优化后的参考方法和临床常规方法同时测量40份单人份血清样本,将2种方法检测结果进行回归分析。根据美国临床实验室标准化学会(CLSI)EP14-A3文件要求对常规方法使用的校准品进行互换性分析。比较优化前后尿酸检测结果。结果尿酸参考方法优化前后SRM 909C、RELA20B、RELA21A的测定结果均在国际临床化学和检验医学联合会(IFCC)等效限范围内(±3.25%),SRM 909C优化前后的测量结果均在其证书范围内[(278.57±5.95)μmol/L]。优化后的重复性明显提高,实验室内精密度虽然改善不明显,但其低值精密度有很大改善,达到实验室对精密度的要求[变异系数(CV)<2%)。优化后的线性相关性(r2=0.9999)更好,斜率更接近1,截距更接近0。尿酸常规方法在医学决定水平110、480、640μmol/L处的预期偏移分别为-15.86%、-2.03%、-1.01%。2个浓度水平的校准品均超出95%可信区间,参考方法和常规方法没有互换性。结论优化后的血清尿酸参考方法有更好的精密度和线性相关性,可以为临床常规测量程序的建立和溯源提供一定的参考。

Objective To optimize serum uric acid reference measurement produce(reference method),and to provide a reference for the establishment of conventional systems.Methods The reference methods of serum uric acid recommended by American Association for Clinical Chemistry(AACC)were established and optimized(centrifugation for 40 min and recentrifugation for 15 min),and accuracy verification was performed by the National Institute of Standards and Technology(NIST)standard reference method(SRM)909C and RELA20B,RELA21A.High,medium and low clinical residual serum samples were collected,and each concentration value was measured for precision verification.Totally,6 concentration gradients were configured for linear evaluation.The optimized reference method and clinical conventional method were used to measure 40 individual serum samples simultaneously,and the results of the 2 methods were analyzed by regression analysis.According to the Clinical and Laboratory Standards Insititute(CLSI)EP14-A3,interchangeability analysis of calibrators used in conventional methods was performed.Results The results of SRM 909C,RELA20B and RELA21A measured before and after the optimization of reference method were all within the equivalent limit of the International Federation of Clinical Chemistry and Laboratory Medicine(IFCC)(3.25%),and the results of SRM 909C before and after the optimization were also within the certificate range[(278.57±5.95)μmol/L].After optimization,the repeatability precision was improved obviously.Although the repeatability precision was not improved obviously,the low-value precision was improved,and it met the precision requirement of laboratory[coefficient of variation(CV)<2%].The optimized linear correlation(r2=0.9999)was good,the slope was closer to 1,and the intercept was closer to 0.The expected biases of conventional method at medically determined levels 110,480 and 640μmol/L were-15.86%,-2.03%and-1.01%,respectively.The 2 calibrators exceeded the 95%confidence interval,so there was no interchangeability between the reference method and the conventional method.Conclusions The optimized serum uric acid reference method has good precision and linear correlation,which can provide a reference for the establishment and traceability of clinical conventional measurement procedure.