血清电解质钠、钾、镁、钙离子正确度验证物质的定值及应用

Value assigned and application of trueness verification materials of serum electrolytes

目的对血清电解质钠(Na)、钾(K)、镁(Mg)、钙(Ca)正确度验证物质应用离子色谱参考方法准确定值,并用于北京市临检中心正确度验证。方法应用建立的离子色谱参考方法,对已研制的3个浓度水平的(批号为BCCL01、BCCL02和BCCL03)人血清基质电解质正确度验证物质进行定值,采用美国国家标准与技术研究院(National Institute of Standards and Technology,NIST)电解质标准参考物质(standard reference material,SRM)SRM 919b、SRM 918b、SRM 929a和SRM 915b进行量值传递。将NIST电解质标准物质配制5个浓度水平的钠、钾、镁、钙复合离子标准溶液,并建立标准曲线,对低、中、高3个水平正确度验证物质进行定值,计算相应不确定度。应用此物质在北京地区23家实验室开展正确度验证计划,正确度验证样本由北京市临床检验中心发放并按时统计汇报结果。依据美国临床实验室标准化协会(Clinical Laboratory Standards Institute,CLSI)EP-17A2,采用协方差的模型和Westgard模型来估算实验室总误差。结果3个批号血清电解质正确度验证物质定值结果钠为125.6~159.1 mmol/L,钾为6.134~3.027 mmol/L,镁为1.389~0.539 mmol/L,钙为3.083~2.197 mmol/L。Westgard模型与参加实验室100%通过率结果相近,而协方差模型结果仅与60%通过率结果相近。结论本研究应用准确可靠的离子色谱参考方法为电解质钠、钾、镁、钙正确度验证物质定值,可用于评价临床实验室4种阳离子常规检测方法的准确性。应用Westgard模型估算相比于协方差模型更能反映实验室的检测水平,所以推荐临床实验室在测定血清阳离子时使用Westgard模型估算总误差。

Objective To determine the accurate values of serum electrolytes sodium(Na),potassium(K),magnesium(Mg)and calcium(Ca)by ion chromatography reference method,and to apply to the trueness verification of Beijing Center for Clinical Laboratories.Methods Using the established reference method by ion chromatography,the developed three concentration levels(batch numbers BCCL01,BCCL02 and BCCL03)of human serum matrix electrolyte correctness verification materials were determined,and the electrolyte standard reference materials standard reference material(SRM)919b,SRM 918b,SRM 929a and SRM 915b from the National Institute of Standards and Technology(NIST)were used for quantity transfer.The five levels of sodium,potassium,magnesium and calcium composite ion standard solutions with NIST electrolyte reference materials were prepared to standard curves,the low,medium and high levels correctness verification materials were assigned values and the corresponding uncertainty were calculated.This substance was used to carry out the correctness verification plan in 23 laboratories in Beijing.The correctness verification samples were distributed by Beijing clinical testing center and the results were statistically reported on time.According to Clinical Laboratory Standards Institute(CLSI)EP-17A2,the covariance model and Westgard model are used to estimate the total laboratory error.Results The determination results of three batches of serum electrolyte sodium from correctness verification substance were 125.6-159.1 mmol/L respectively,potassium was 6.134-3.027 mmol/L respectively,magnesium was 1.389-0.539 mmol/L respectively,calcium was 3.083-2.197 mmol/L respectively.The results of Westgard model are similar to the results of 100% passing rate of participating laboratories,while the results of covariance model are only similar to the results of 60% passing rate.Conclusion In this study,the accurate and reliable reference method of ion chromatography is used to assign value of electrolyte sodium,potassium,magnesium and calcium,which can be used to evaluate the accuracy of conventional detection methods in clinical laboratory.Compared with the covariance model,Westgard model is more suitable for the reflection of detection level of the laboratory,so it is recommended that clinical laboratories use Westgard model to estimate the total error in the determination of serum cations.