血清肌酐测定基质效应的研究

目的 评价血清肌酐测定常规方法的校准偏差及肌酐制备物常在常规方法上的基质效应.方法 根据美国临床实验室和标准化协会(CLSI)EP14-A2评价方案,同位素稀释液相色谱串联质谱法(ID-LC/MS/MS)测定血清肌酐的方法为比对方法,15种常规肌酐测定系统(7种酶法,8种苦味酸法)为待评方法,测定40个新鲜冰冻人血清和36种制备物的肌酐浓度,评价制备物的基质效应和测定系统的校准偏差.结果 大部分商品制备物(29/30)在苦味酸法系统上表现出基质效应,少部分商品制备物(13/30)在部分酶法系统上表现出基质效应.我中心6个制备物在所有15个系统上均未观察到基质效应.所有常规系统新鲜冰冻血清测定值与比对方法测定值间均呈较好的直线相关,所有苦味酸法和部分酶法测定肌酐方法存在校准偏差.结论 基质效应和校准偏差存在于常规肌酐测定方法,必须重视这些因素,提高肌酐测定结果的正确度和可比性.

Evaluation of matrix effects of reference materials in serum creatinine measurements

Objective To evaluate the trueness of routine systems for serum creatinine measurement and the matrix effects of creafinine reference materials on the systems. Methods The Clinical and Laboratory Standards Institute (CLSI) EP14-A2 protocol was used for the study and an isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) method was used as the comparative method. Fory fresh patient specimens, 15 EQA materials, 13 calibrators, two control materials and 8 frozen serum materials were measured by the comparative method and 15 routine systems (7 enzymatic methods and 8 alkaline picrate methods). Matrix effects were assessed by using the EP14-A2 procedure, and the trueness of the evaluated methods were assessed by comparing the results of the 40 fresh patient specimens obtained with the evaluated methods and the comparative method. Results Tweenty-nine of 30 commercial materials showed matrix effects on the alkaline picrate systems, and 13 of the commercial materials showed matrix effects on the enzymatic systems. Fresh frozen serum materials prepared at the National Center for Clinical Laboratories showed no matrix effect on all 15 routine systems. Calibration biases were observed on 8 alkaline picrate systems and some enzymatic methods. Conclusions Matrix effect, calibration bias and nonspecificity in serum creatinine measurements. Continued efforts are needed for improving the trueness and comparability of serum creatinine measurements.