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.     

血清总胆固醇测定的基质效应研究

目的 评价血清胆固醇常规方法对常见胆固醇参考物质的基质效应和常规方法的校准偏差.方法 用高效液相色谱测定血清总胆固醇的方法为对比方法,用胆固醇氧化酶法的6种常规测定系统为待评方法,测定30个新鲜冰冻人血清和37种制备物的总胆固醇.将两法测定新鲜人血清的结果作直线回归,求得Y预测值双侧95%的允许区间,评价制备物的基质效应.通过分析新鲜冰冻人血清样品常规方法和对比方法结果的差异,评价测定系统的校准偏差.结果 胆固醇制备物的基质效应依品种而异,冰冻血清几乎没有基质效应,冻干血清表现为负基质效应,乙醇基质校准液呈正基质效应.所有系统新鲜冰冻血清测定值同对比方法测定结果均呈较好的直线相关.A,B,E系统显负偏差,C,D,F系统显正偏差,但偏差大多处于临床可接受的范围内,可满足临床需求,个别测定系统需进行改进.结论 在我国血清胆固醇测定系统上,制备物的基质效应普遍存在,部分常规系统存在校准偏差.为实现检验结果的准确性和实验室间的可比性,临床标准化工作势在必行.     

血清尿酸测定的基质效应

目的检测21种样本(血清及制备物)的尿酸水平,评价其对13种尿酸常规检测系统的基质效应。方法根据卫生行业标准WS/T356-2011,以同位素稀释液相色谱串联质谱法(ID-LC/MS/MS)为比对方法,将不同厂商生产的13种尿酸检测试剂盒(均为酶法)分别与日立7180全自动生化分析仪组成常规检测系统,并以此为评价方法。样本包括4种校准品、5种室间质量评价(EQA)样本、6种质控品、3种制备物(1种猪血清和2种水溶液制备物)、1种美国国家标准与技术研究院(NIST)的标准参考物质(SRM)909c、2种国际临床化学与检验医学联合会(IFCC)检验医学参考实验室外部质量评价计划(RELA)样本,共计21种。用比对方法和评价方法分别测定40份新鲜冰冻血清和上述21种样本。将比对方法和评价方法尿酸测定结果进行直线回归分析,求得Y预测值双侧95%可信区间,评价血清及制备物的基质效应。结果 21种评价样本中有5种基质为新鲜血清或冻干血清的样本(2种EQA正确度验证血清、2种RELA样本和SRM 909c)在所有常规检测系统中均未观察到基质效应。2种校准品(朗道和迪瑞)仅在1种常规检测系统中有基质效应。5种EQA样本中除用于正确度验证的新鲜血清样本外,其他冻干血清样本在较多常规检测系统中存在基质效应。6种质控品中有4种在所有常规检测系统中无基质效应,2种高值质控品显示负基质效应。结论新鲜血清基质样本是可靠的检测样本,可在标准物质制备、质控品制备和EQA中使用。某些校准品在非配套系统中可能存在基质效应而产生校准偏差,因此在使用这些校准品前最好经过基质效应评价或方法验证。     

血清ALT与AST测定的基质效应评价

摘要：目的：评价7种室间质量评价（EQA）材料和4种市售材料在9个检测系统上测定血清ALT和AST的基质效应。 方法：参照美国临床实验室标准化协会(CLSI)EP14-A2指南,根据ALT和AST的参考方法建立不含磷酸吡哆醛的比对方法。9个检测系统的常规方法为待评方法。用比对方法和待评方法同时测定新鲜人血清、EQA材料及市售材料的ALT和AST水平,评价非血清样品的基质效应。 结果：ALT测定中1种EQA材料对所有检测系统均表现基质效应,AST测定中2种EQA材料对所有检测系统无基质效应,其他材料视系统的不同而表现出不同的情况。 结论：基质效应影响血清ALT和AST测定的准确性和可比性,应充分重视基质效应对临床检验量值溯源的影响。     

参考方法在丙氨酸氨基转移酶测定标准化中的应用

目的 调查不同检测系统使用经参考方法赋值的冰冻人血清样本作为校准品进行校准后,不同来源样本丙氨酸氨基转移酶(ALT)测定结果的可比性与准确性的改变程度.方法 5份经4家候选参考实验室应用不含磷酸吡哆醛的ALT参考方法定值的冰冻人混合血清样本用于评价广州地区10个不同检测系统ALT催化活性结果的可比性与准确性.其中一个样本用作校准品校准各系统.比较校准前后各系统间新鲜血清样本与商品制备物测定结果的变异与偏倚.结果 校准后,各检测系统间新鲜血清测定结果的变异由11.90%～8.60%下降到6.78%～2.30%,偏倚则从-12.52%～-8.44%下降到-3.36%～-0.08%.校准后,常规系统测定新鲜血清结果与参考方法的回归曲线的斜率和截距比校准前更接近1和0;而商品制备物测定结果校准后的斜率和截距则无明显改善.结论 采用定值冰冻人血清样本作为校准品可以改善不同检测系统测定结果的准确性和可比性,但由于基质效应的存在不能改善商品制备物测定结果的可比性.     

血清总甘油测定基质效应的研究

目的 评价28种质控血清或校准物在8种总甘油常规检测系统下的基质效应,并评价常规系统校准的准确性.方法 以同位素稀释液相色谱串联质谱测定m清总甘油的方法为对比方法,用甘油氧化酶法的8种常规测定系统为待评价方法,测定20份人新鲜血清和28种制备物中的总甘油.将两法测定人新鲜血清的结果作直线回归,求得Y值双侧95%的预测区问,评价制备物的基质效应.通过分析新鲜血清样本的测定结果评价常规系统校准的准确性.结果 制备物在进口A、B、C系统和国产D系统巾表现正基质效应,进口D系统正、负基质效应均有以正效应为主,国产A、B系统正、负基质效应均以负效应为主,只有1个制备物对国产C系统有较弱的基质效应.同对比方法相比,国产A、D系统存在正校准偏差,进口A、B、C、D和国产B系统1竽在负偏差,国产C系统不存在校准偏差.结论 我国血清总甘油的部分常规检测系统存在校准偏差,部分质控物和校准物存在基质效应.为实现检验结果的准确性和实验室问的可比性,临床标准化工作势在必行.     

胆固醇检测试剂的校准偏差和基质效应

目的 试验胆固醇试剂的校准偏差和基质效应。方法 用酶法和高效液相色谱法测定新鲜血清和不同基质类型的校准注胆固醇浓度,比较两法的测定结果。结果 多数被检试剂－校准物系统存在校准偏差（＝３．５％至＋９．４％）;所有被检试剂对冻干血清、胆固醇水溶液等制备物有不同程序的基质效应,而冰冻人血清基质效应最小。结论 制备胆固醇校准物需充分认识指定度剂条件下的基质效应,根据新鲜血清测定结果,做出正确定值。     

天门冬氨酸氨基转移酶“改良参考方法”的建立及其用于测定结果的可比性研究

目的应用不含磷酸吡哆醛的参考方法评价不同实验室间天门冬氨酸氨基转移酶（AST）测定结果的可比性。方法参照国际检验医学溯源联合会（JCTLM）推荐的参考方法及日本临床化学会相关文件,建立不含磷酸吡哆醛的AST参考方法。根据美国临床实验室标准化协会（CLSI）系列文件对该方法的精密度、正确度、线性范围等性能进行评价。应用该参考方法对新鲜血清进行赋值作为校准品校准广州地区10家实验室的常规检测系统,比较校准前、后新鲜血清、能力验证样本以及市售制备物质测定结果间的偏倚,进行检验结果的可比性评价。结果改良参考方法的批内不精密度〈1%,总不精密度〈2%;检测日本临床化学会酶参考品结果均在其不确定度允许范围内,参加参考实验室网络赋值计划测定结果与均值比较在等效限内。改良AST参考方法分析测量范围上限为413.6 U/L。校准前新鲜血清测定结果与参考方法测定结果之间偏倚〉20%的所有11个测定结果中,有10个测定结果来源于用理论K值计算酶活性的检测系统;校准前新鲜血清组最大偏倚为-25.0%,平均偏倚为9.3%;使用改良参考方法定值的酶校准品校准后,最大偏倚降为12.3%,平均偏倚降为2.1%。而能力验证样本和市售制备物中AST测定结果的平均偏倚在校准前后则变化不大,市售制备物组平均偏倚反而略有升高。结论应用参考方法定值的新鲜血清作为校准品进行校准是实现不同检测系统检验结果一致性和可比性的有效途径,非新鲜血清样本存在不同程度的基质效应。     

EDTA-K2抗凝剂对干式法检测ALT的基质效应分析

目的观察EDTA-K2抗凝剂对罗氏干式法检测丙氨酸氨基转移酶(ALT)的基质效应。方法罗氏Cobas P800全自动生化分析仪、罗氏Cobas ALT测定试剂盒、罗氏Cobas校准品及质控品组合为比较的检测系统(X),Reflotron快速干式生化分析仪、配套ALT检测试纸及质控条组合为待评价的检测系统(Y),分别对新鲜血清样品和EDTA-K2抗凝血浆进行ALT比对检测,参考EP14-A文件介绍的方法,对新鲜血清样品的结果做直线回归分析,绘出估计值(Y)的95%预期区间,用于观察EDTA-K2抗凝血是否存在基质效应。结果 EDTA-K2抗凝血浆的部分对比点在新鲜血清对比点估计值的95%可信区间以外,结果呈线性偏差。结论 EDTA-K2抗凝剂对罗氏干式法检测ALT引入的基质效应,浓度越高,基质效应越明显。     

16种17-羟孕酮制备物基于两种评价方案的互通性研究

目的应用两种互通性评价方案评价16种17-羟孕酮制备物的互通性。方法互通性研究,收集2018年2月至2019年6月之间北京医院检验科的新鲜人血清共52份。根据美国临床和实验室间标准化研究所文件(CLSI)EP14-A3和国际临床化学和检验医学联合会(IFCC)互通性评价工作组报告,以血清17-羟孕酮同位素稀释液相色谱串联质谱法(ID-LC/MS/MS)为比对方法,3种临床常规分析系统(1种放射免疫法,2种LC/MS分析法)为待评方法,一同测定52个人血清样本和16种制备物的17-羟孕酮浓度,评价制备物质的互通性。结果综合两种互通性评价结果,所有正确度验证材料和国家甾体激素标准物质在LC/MS分析系统中都显示出良好的互通性,6/9的EQA材料在三种常规分析系统中都显示出互通性。其中所有材料在偏倚差值法中所有材料的LC/MS分析系统中都显示出良好的互通性。结论两种互通性评价结果有所差异,使用新鲜冰冻人血清作为血清17-羟孕酮的质评材料均能满足互通性要求。     

Comparability of four clinical laboratory measurement methods for GGT and commutability of candidate reference materials

BackgroundThis study was conducted to evaluate the progress in the standardization of the gamma‐glutamyl transferase (GGT) to achieve metrological traceability of routine in vitro diagnosis (IVD) medical devices.MethodsWe collected 25 single fresh frozen serum samples for GGT analysis. Candidate reference materials (RMs), calibrators, internal quality controls (IQC), and external quality assessment (EQA) materials from the National Center for Clinical Laboratory (NCCL), Beijing Center for Clinical Laboratory (BCCL), and College of American Pathologists (CAP) were randomly added to these serum samples. A total of 42 samples were examined using IFCC reference method and four different IVD medical devices to perform the comparability and commutability study.ResultsThe four IVD medical devices achieved trueness assessment within the measurement range. Linear analysis showed the agreement of Siemens ADVIA 2400, Hitachi 7600‐020/BioSino, Beckman AU 5800, and Roche Cobas 501 with the reference method. These assay pairs were comparable at the medical decision levels. The GGT in‐house candidate RMs, and Beckmann and Roche calibrators were all within the limits of the 95% prediction intervals, the commutability of BioSino calibrators was indeterminate, and some internal and external quality controls were not commutable for comparisons of certain IVD medical devices vs the reference method.ConclusionsBy comparing with the reference method, we found that performance of GGT conventional measurement systems to be traceable to the higher order references was improved. The commutable materials for calibration and trueness controls of routine methods were significant to promote the standardization of GGT analysis.     

基体效应的实验评价

目的评价校准品和质控品的基体效应。方法按照美国临床实验室标准化委员会(NCCLS)文件EP14-A,以Beckman Coulter公司检测系统(BC)和5家国产试剂(分别用A、B、C、D、E表示)-日立仪器检测系统为被评价方法,以罗氏公司试剂(Roche)-日立仪器检测系统为比较方法,用被评价方法和比较方法检测40份新鲜患者样本、罗氏公司cfas、伊华公司(YH)校准品和市售的6种质控品(分别用a1、a2、b1、b2、c1、c2表示)的丙氨酸氨基转移酶(ALT)活性。用直线回归方法统计数据,以回归直线的■估计值■的95%可信区间,估计这8个处理过的样本在6种检测系统中的基体效应。结果2种校准品和a1、a2、b1质控品在6种检测系统中没有基体效应存在,质控品b2在国产试剂C、D、E检测系统,c2在E检测系统存在基体效应。结论在室间质评和常规检测中应重视校准品、质控品在不同检测系统间的基体效应,以供合理选择,提高检测结果的准确性。     

Measurement of urea in human serum by isotope dilution mass spectrometry: a reference procedure.

BACKGROUND: A reference measurement procedure is needed to demonstrate the traceability of results of urea measurements in human serum. We developed a measurement procedure using the principle of isotope dilution gas chromatography/mass spectrometry. METHODS: [(13)C,(15)N(2)]Urea as internal standard was added to a serum sample and equilibrated with endogenous nonlabeled urea. For the preparation of calibrators, the same amount of labeled urea was mixed with known amounts of nonlabeled urea. The serum samples were treated with ethanol to remove proteins by precipitation. The labeled and nonlabeled urea of the samples was converted into a trimethylsilyl derivative of 2-hydroxypyrimidine. The gas chromatography/mass spectrometry system was adjusted to monitor m/z 153 and 168 for the nonlabeled urea derivative and m/z 156 and 171 for the isotopically labeled analogs. The results of the determination were calculated from peak ratios by a hyperbolic calculation function based on the theory of isotope dilution analysis. RESULTS: The procedure was applied to control samples and patient samples and evaluated with respect to its trueness and precision. The standard uncertainty of the results was 0.47-1.72%. CONCLUSIONS:This reference measurement procedure allows values to be assigned to controls and calibrators that are traceable to the primary urea reference material of NIST and, therefore, to the Système International unit "mole" with a low degree of uncertainty. This procedure provides a tool for the highly accurate determination of urea in control materials as well as in patient sera.     

Commutability of possible external quality assessment materials for progesterone measurement

BackgroundThe commutability of control materials used for external quality assessment (EQA) programs is of great importance. Evaluating the commutability of control materials is crucial to assess their suitability for EQA programs.MethodsForty-eight individual patient serum samples, commercial EQA samples, human serum pools (HSPs), commercially available sterile filtered charcoal stripped serum (CS) and swine serum were analyzed using the isotope dilution liquid chromatography-tandem mass spectrometry (ID LC-MS/MS) comparative method and six immunoassays for progesterone. The commutability was assessed according to the EP14-A2 guideline and the difference in bias approach, respectively.ResultsAccording to the EP14-A2 guideline, HSPs and CS were commutable for all the tested immunoassays, while swine serum showed positive matrix effects in some assays. Based on the difference in bias approach, a large number of inconclusive and noncommutable results appeared.ConclusionsThe commutability of the processed materials varied depending on which evaluation approach and criterion was applied. Noncommutability of the EQA materials was observed. And HSPs and CS were possible commutable candidate control materials according to the EP14-A2 guideline.     

LC-MS/MS检测血清25-羟基维生素D替代校准品基质的选择与评价

目的 探讨如何选择和评价液相色谱-串联质谱(LC-MS/MS)检测血清25-羟基维生素D[25(OH)D]替代校准品基质.方法 分别用4％牛血清白蛋白(BSA)溶液和30％乙醇水溶液2种替代基质,配制25(OH)D的标准溶液并绘制标准曲线.通过比较内标在不同基质中的响应值差异及基质效应混合实验、准确度验证,对替代基质进...     

Trueness verification in European external quality assessment schemes: time to care about the quality of the samples

An external quality assessment (EQA) survey on 14 fresh-frozen, single-donation sera assigned with reference measurement procedure (RMP) values revealed a mean bias of + 5.2% and + 3.7% for the cholesterol oxidase and the photometric glucose oxidase procedure groups, respectively. Conversely, on lyophilized sera, the same procedure groups showed almost bias-free results, the differences from the RMP values being only -0.8% for cholesterol and + 0.7% for glucose. These data, which are in fairly good agreement with the literature, suggest the existence of artificial matrix effects in processed materials. Therefore they indicate that, currently, assessment of trueness is hampered in many European EQA schemes, as most of them use lyophilized sera. This approach may give a false impression about the trueness of laboratory results as well as carrying the risk that laboratories calibrated on the RMP values of the survey samples could make errors in patient testing. Consequently, if European EQA is willing to fulfil a post-market vigilance function of the performance of in vitro diagnostic medical devices, then the time has come to tackle the problem of the quality of the survey samples. EQA organizers urgently need to make an effort to seek out materials that analytically behave like authentic clinical specimens. In the meantime, alternative approaches should be used. Although not ideal, the special survey described in this article is one of the possibilities. Naturally, it implies logistic problems and increased costs for the individual EQA schemes. However, both can be overcome with the cooperation of the predominantly nationally organized schemes.     

Commutability and traceability: their repercussions on analytical bias and inaccuracy

The commutability of calibrators and accuracy control materials affects the traceable link between patient sample results and standards. We sought to identify the repercussions of commutability on various aspects of laboratory practice (calibration, control of bias and accuracy assessment) and to discover the solutions that can reduce the problems produced by non-commutability with presently available resources. Ten serum constituents, ten comparison procedures and 37 analytical procedures were studied. The information concerning accuracy and bias provided from materials found to be commutable in previous works was challenged with native serum results for each routine and reference method compared, using Passing–Bablok regression and decision limits derived from biological variation. We found that: (1) Use of commutable control materials did not assure reliable information on the bias (systematic component of analytical error) of analytical procedures, and (2) Results from native serum and commutable controls were very highly concordant, indicating that these materials provide a good indication of the inaccuracy (total analytical error) of results. We suggest that the performance of individual laboratories would be better evaluated by occasional use of native sera with values assigned by reference methods in EQAS schemes. Moreover, our findings support the idea that manufacturers should assign values to calibrators using reference methods and native sera to reduce matrix effects and promote traceability.