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.     

参考方法检测3种血清酶结果的国际比对分析

摘要：目的：分析我室2008及2009年参加国际临床化学联合会(IFCC)的参考实验室GGT、CK、LDH的国际比对计划的结果,评估我室所用参考方法的检测质量及完善程度。 方法：用IFCC推荐的酶学活性测定（37 ℃）参考方法测定人血清GGT、CK、LDH,用酶有证参考物质评估参考方法的准确度,同时测定国际RELA比对样本,并对回报数据进行分析处理。 结果：2008年度的国际RELA比对结果室内变异系数(CV) 在0.67%~1.13%之间,与均值的偏倚在±3.50%以内;2009年度的国际RELA比对结果室内CV均在0.88%~1.30%之间,GGT和CK测定结果的偏倚在±1.00%以内,但LDH测定结果的偏倚大于2008年。2008、2009年的GGT、CK、LDH的比对结果均在IFCC公布的等效限内。 结论：本参考实验室所用的GGT、CK、LDH的检测方法比较成熟稳定。     

国内4厂家15套血清葡萄糖检测系统精度的比对研究

目的:了解国产葡萄糖检测试剂在不同自动化分析仪上测定结果的精度.方法:向参加调查的国内4个葡萄糖试剂生产厂家发放经美国CDC推荐的血清葡萄糖己糖激酶参考方法定值的5水平候选葡萄糖标准物质,各厂家自行选取自动生化分析仪,分别采用试剂配套校准品和第2水平候选标准物质校准后测定.结果:15个检测系统采用试剂配套校准品校准后5水平候选标准物质测定结果的变异均明显高于以C2为校准品校准后测定结果的变异;经原厂校准品校准后,8个GOD法检测系统的变异明显高于7个HK法检测系统的变异,但以C2为校准品校准后GOD法与HK法检测系统的变异无此明显差异.15个检测系统以原厂校准品校准后C1～C5候选标物的偏倚分别是-2.92%～11.68%、-3.37%～9.79%、-3.75%～8.75%、-3.11%～9.55%、-4.38%～8.28%,其中3个检测系统的偏倚超出了葡萄糖常规测定方法中欧洲生物学目标和计算出的生物学允许的总误差5.5%,2个检测系统的偏倚超出了美国标准的总分析误差6.0%,1个检测系统的偏倚超出了CLIA'88能力比对检验的可接受偏差10%的要求;以C2为校准品校准后C1～C5候选标物的偏倚分别是-1.95%～3.57%、-1.52%～1.85%、-2.72%～2.27%、-1.82%～2.9%、-2.83%～2.19%.15个检测系统的偏倚均小于欧洲生物学目标和计算出的生物学允许的总误差5.5%的要求,同时小于CLIA'88能力比对检验的可接受偏差10%的1/2.结论:部分常规血清葡萄糖检测系统的偏倚较大,采用具有互通性的候选标物为校准品可以提高常规检测系统测定结果的精密度和正确度.     

以LDH为例来探讨具有溯源性和互换性的校准品在临床生化应用中的重要性

目的通过在临床实验室使用具有溯源性和互换性的校准品,寻求血清酶测定标准化的新途径。方法以乳酸脱氢酶(LDH)为例,收集混合血清,由4家酶学参考实验室联合赋值,制备具有溯源性和互换性的参考物质。参加试验的8个实验室先使用自己的校准品,在校准通过后,将高中低3个水平的血清样本和参考物质各测定3次,记录检验结果;再使用具有溯源性和互换性的参考物质作为校准品校准后,重复测定高中低3个水平的血清样本和参考物质各3次,记录检验结果。计算8家实验室在使用具有溯源性和互换性的参考物质作为校准品校准前后,参考物质检测结果与靶值的偏倚和高中低3个水平的血清样本LDH检测结果的变异系数(CV%)。结果使用具有溯源性和互换性的参考物质参后,参考物质检测结果与靶值的偏倚由6.80%降到1.40%;高中低3个水平的血清样本LDH检测结果的变异系数CV由11.41%,9.93%和9.87%降到了4.13%,3.55%和3.80%。结论在临床实验室使用具有溯源性和互换性的参考物质作校准品,能大大降低实验室间结果的正确度和精密度,提高检测结果的准确性,有利于各个实验室各设备间结果的标准化和一致性。     

进口配套γ谷氨酰转移酶检测系统测定结果精密度和正确度调查

目的 调查国内临床实验室使用的6个系列进口配套γ谷氨酰转移酶(GGT)检测系统测定结果的精密度和正确度,为实验室酶学测定确定具有准确性的目标系统提供依据.方法 国内两家候选酶学参考实验室使用国际临床化学和检验医学联合会(IFCC)推荐的GGT参考测量方法,为5个活性浓度水平的新鲜冰冻混合人血清确定靶值,实验人员用基于厂家配套校准品等方式校准的6个厂家配套检测系统对血清样本进行检测,每个厂家均由独立分布于5个实验室的5台仪器组成(其中1个厂家为2台),各台仪器于实验前由各厂家工程师进行了一次日常维护.收集检测数据,统计同一厂家检测系统、不同厂家检测系统间检测结果的精密度,及各厂家检测系统测定结果均值与参考方法靶值的偏倚.结果 6个厂家(A、B、C、D、E、F)配套测定系统间5个水平检测结果的差异为16.1%～35.4%;不同检测系统间5个水平样本测定结果的变异系数(CV)为5.3%～8.8%;同厂家配套检测系统间5个水平样本测定结果CV分别为A:2.17%～5.07%、B:4.21%～10.98%、C:0.52%～2.38%、D:1.35%～2.59%、E:0.23%～1.54%、F:1.83%～2.38%.各厂家测定系统检测结果均值与靶值的偏倚分别为A:0.43%～8.41%、B:-1.49%～-13.04%、C:11.2%-17.73%、D.0.19%～4.62%、E:-0.30%～-2.63%、F:-0.46%～7.90%.调查显示:有2个厂家结果在本次调查的浓度范围内偏倚均小于1/4美国<临床实验室改进法案修正案>(CLIA'88)规定的允许总误差(TAE);有2个厂家结果在特定浓度范围内偏倚可满足1/4 TAE;有2个厂家结果的偏倚在大多数情况下近于或大于1/2 TAE.调查同时显示:在高、低浓度水平,有半数以上调查厂家结果的偏倚大于1/4 TAE.结论 不同厂家配套检测系统间结果的均值存在明显差异,其结果的可比性明显劣于同一厂家检测系统间的可比性;厂家应进一步保证其检测系统经参考方法校正,并应注重对检测系统测定线性的校正.     

人血清甲胎蛋白候选标准物质的制备

目的研制3个水平冰冻混合人血清甲胎蛋白(AFP)候选标准物质。方法使用体检健康者肉眼无溶血、脂血和黄疸的混合血清作为稀释血清,将AFP高值血清稀释成3个浓度水平,通过微孔滤膜过滤除菌后分装于冻存管中。按照ISO Guide35的要求,对人血清AFP候选标准物质进行均匀性和稳定性检验。用化学发光免疫分析仪将制备的AFP候选标准物质与WHO标准物质(72/225)同批检测,将结果进行比较,对候选标准物质定值。将3个水平候选标准物质发放到北京市34家实验室用不同常规分析系统测定。结果均匀性检验方差分析结果显示,制备的候选标准物质均匀性良好。在室温18~25℃保存可稳定5d;2~8℃可稳定10 d;-15~-20℃可稳定6个月;-80℃保存在已监测6个月内稳定性良好,长期稳定性计划监测2年。3个水平的AFP候选标准物质定值为(26.37±1.81)ng/m L、(123.52±7.54)ng/m L、(3 614.70±340.31)ng/m L。34家实验室测定结果显示,不同品牌检测系统测定结果均值与定值偏倚均12.5%(1/2 CLIA'88 TEa)。结论 3个水平冰冻混合人血清AFP候选标准物质均匀性、稳定性良好。定值可靠,在常规分析系统中互通性良好。可用于临床实验室常规检测方法的校准/校准验证、试剂厂家常规校准品的定值、室间质量评价及正确度验证计划。对申报为人血清AFP国家二级标准物质提供了依据。     

血清肌酐参考方法的建立及其在正确度调查中的应用

目的建立同位素稀释液相色谱串联质谱(ID-LC/MS/MS)测定人血清肌酐的参考方法,并运用于临床实验室正确度调查新鲜冰冻血清样本靶值的确立。方法按照国际检验医学溯源联合委员会(JCTLM)推荐方法,建立本实验室肌酐参考方法,利用参考物质SRM909c及RELA比对样本考察所建方法的精密度与准确度,并将建立的参考方法用于上海地区小分子正确度调查新鲜冰冻血清肌酐靶值的确立。结果参考方法测量参考物质SRM909c相对偏移为0.69%,测量不精密度2%,初步验证了方法的准确度和精密度。正确度调查样本201411、201412、201421、201422酶法检测结果与参考方法测定值的相对偏移分别为14.97%、-2.77%、-1.37%、-1.92%;苦味酸法检测结果与参考方法测定值的相对偏移分别为21.39%、2.10%、6.22%、2.38%。除201411样本(为低浓度样本)外,其余样本不同常规分析系统测定的血清肌酐浓度与参考方法赋值结果的相对偏移均不超过8%。结论建立的ID-LC/MS/MS测定血清肌酐的方法精密度、准确度均较好,靶值的确定对实验室检测结果分析有重要意义,该参考方法的建立有望在上海地区临床实验室正确度计划中发挥一定作用,并建议临床实验室重视低浓度下肌酐测量的准确度和一致性。     

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。     

五种血脂检测系统测定结果的可比性调查

目的 通过比较5个常用的不同血脂检测系统在使用参考方法赋值新鲜血清校准前后的结果可比性,探讨实现血脂检测一致化的方法。方法采用室内质控总变异(CV%)评价5个血脂检测系统的不精密度。参考美国临床及实验室标准化委员会(CLSI)EP 9A2方案,比对54份新鲜患者血清在5个临床常用的总胆固醇(TC)、三酰甘油(TG)检测系统上的结果,并将不同检测系统结果与均值进行偏倚评估。其中8份样本采用参考方法定值,并评估不同系统的偏倚。尝试采用参考方法赋值的新鲜冰冻血清校准以上检测系统,并使用相同的54份患者新鲜血清再次进行比对及偏倚评估。比对校准前后54份样本在不同检测系统测定的变异。结果 5个检测系统TG总不精密度在3.76%～23.65%之间,TC在2.19%～23.43%之间。各系统结果相关良好,TG和TC的r值分别在0.996 7～0.999 6和0.956 2～0.996 7之间,但系统间结果存在较明显的偏差,各系统最大百分偏差TG在14.72%～34.21%,TC在3.11%～14.57%。用参考方法赋值的血清对不同系统进行校准之后系统间偏差和变异均明显降低。结论用参考方法赋值的新鲜血清校准不同的血脂检测系统,可以有效地提高测定结果的一致性。     

冰冻混合人血清酶校准品的赋值

目的探讨用酶学参考实验室网络为冰冻混合人血清酶校准品赋值以获得具有互通性与溯源性的酶校准品。方法根据要求收集患者血清,按酶学校准品制备程序制备所需浓度水平的混合人血清酶校准品。由北京市临床检验中心(BCCL)组织国内6家候选酶学参考实验室组成实验室网络,用国际临床化学和检验医学联合会(IFCC)推荐的丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)、γ-谷氨酰转移酶(GGT)、肌酸激酶(CK)、乳酸脱氢酶(LDH)参考测量程序,按照BCCL拟定的赋值程序,为冰冻混合人血清酶校准品赋值。结果 6家实验室ALT、AST、GGT、CK、LDH 5项酶赋值结果分别为(112.16±1.94)、(101.37±0.37)、(175.74±1.82)、(370.92±4.48)、(309.69±1.78)U/L;室内质控变异系数(CV)分别为0.33%~1.40%、0.50%~1.24%、0.37%~1.49%、0.50%~1.30%、0.61%~1.11%;冰冻混合人血清赋值的室间CV分别为1.73%、0.36%、1.04%、1.21%、0.58%。5项酶的室间变异与同期国际参考实验室室间质评计划(RELA)的室间变异相近或比其略小。结论 BCCL组织的酶学参考实验室网络血清酶校准品赋值结果满意。     

A novel noninvasive blood glucose monitor

OBJECTIVE: To evaluate the precision and accuracy of a new advanced prototype of a noninvasive blood glucose monitor across a wide range of serum glucose concentrations. RESEARCH DESIGN AND METHODS: An advanced handheld noninvasive glucose monitor prototype was calibrated and tested using patients recruited by the General Research Center of the University of Connecticut Health Center. The monitor, developed by Infratec, uses principles of thermal emission spectroscopy. The noninvasive measurement of tympanic membrane glucose concentration was calibrated to the serum glucose concentration using 432 paired measurements from 20 subjects with insulin-requiring diabetes. This calibration was subsequently tested (results of power analyses) in a blind fashion with 126 paired measurements from six diabetic subjects who require insulin. RESULTS: In vivo measurements demonstrated the reproducibility of the methodology of the noninvasive glucose monitor. Based on the calibration model, predicted glucose concentrations for six subjects were as follows (for 126 data points): SD = 32 mg/dl, mean absolute relative error (%MARE) = 11.6, with a correlation coefficient of r = 0.87. Noninvasive glucose results were also compared with laboratory reference measurements using an error-in-variables method. Clark error grid analysis showed that 100% of the measurements fell within zones A and B (90% in zone A and 10% in zone B). The SD for all noninvasive measured concentrations was 27 mg/dl, %MARE was 8.6, and the correlation coefficient was r = 0.94. CONCLUSIONS: This first independent clinical study of an advanced noninvasive blood glucose prototype based on thermal emission in the mid-infrared spectral region has demonstrated glucose measurements with clinically acceptable accuracy but without the necessity of individual daily calibration.     

重症监护室常用血糖测量方法的一致性研究

目的 评价目前重症监护室(intensive care unit,ICU)常用的4种血糖测量方法与静脉血/血生化仪法的一致性,并分析可能的影响因素.方法 前瞻性序贯纳入2007年11月至2008年1月期间收入北京协和医院内科ICU病房且预期ICU住院时间＞48 h的患者49例,共检测血糖130组,每组均采用毛细血管血/血糖仪法、动脉血/血糖仪法、动脉血/血气分析仪法和动脉血/血生化仪法测量血糖,分别计算上述4种方法与静脉血/血生化仪法(标准法)所测血糖值的差值、相关系数、偏倚校正因子及不一致率,并采用Logistic回归分析影响一致性的因素.结果 毛细血管血/血糖仪法、动脉血/血糖仪法、动脉血/血气分析仪法、动脉血/血生化仪法所测血糖值与标准法所测血糖值的差值分别为:(1.7±1.4)mmol/L,(1.6±1.4)mmol/L,(1.1±1.2)mmol/L,(0.5±1.2)mmol/L,不一致率分别为66.9%,63.8%,40.0%,23.8%.相关系数分别为0.844,0.845,0.895和0.896,偏倚校正因子分别为0.821,0.831,0.914和0.979.红细胞比积减低是毛细血管血/血糖仪法(OR=0.923,P=0.03)和动脉血/血糖仪法(OR=0.921,P=0.014)血糖测量值与标准法不一致的独立危险因素.结论 在重症监护病房,采用血糖仪测量血糖的方法与标准法的一致性均较差,而血气分析仪法则是一致性较好的床旁血糖检测方法.红细胞比积减低可影响血糖仪测量的准确性.

Abstract：

Objective To evaluate the accuracy of five blood glucose measurements commonly used in ICU and to determine the potential factors interfering the accuracy. Method This prospective study carried out in consecutively enrolled 49 patients stayed more than 48 hours in the medical ICU of Peking Union Medical College Hospital from November 2007 to January 2008. A total of 130 blood samples were measured to determine blood glucose with five different methods, and the biochemistry analyzer in central laboratory was regarded as reference method for comparison with other four methods, ( 1 ) capillary blood/glucometer;(2) arterial blood/glucometer; (3) arterial blood/blood gas analyzer; and (4) arterial blood/biochemistry analyzer. The accuracy of a method tested was judged by the difference in level of blood glucose between it and reference method, correlation coefficient, bias correction factor and discrepancy. The independent factors for the discrepancies were identified by multivariate logistic regression. Results The values of differences in level of blood glucose between above four methods and the reference were ( 1.7 ± 1.4) mmol/L,( 1.6 ± 1.4 ) mmol/L, ( 1.1 ± 1.2) mmol/L, and (0.5 ± 1.2 ) mmol/L, respectively. The rates of discrepancy were 66.9%, 63.8%, 40.0% and 23.8%. The correlation coefficients were 0. 844, 0. 845, 0. 895and 0. 896. The bias correction factors were 0. 821,0.831,0.914 and 0. 979. Decrease in hematocrit was statistically associated with the discrepancy between glucometer analysis methods and the reference, with OR of 0.923 for capillary blood ( P = 0.03 ) and 0. 912 for arterial blood( P = 0.014), respectively. Conclusions Glucometer analysis poorly correlated with reference method and blood gas analysis in ICU patients. Decrease in hematocrit significantly increased the degree of discrepancy in glucose measurements between glucometer analysis and the reference.     

血清葡萄糖参考方法的复现及与临床常用检测方法的比对研究

目的 复现血清葡萄糖测定己糖激酶的参考方法 (紫外分光光度法),对此方法 进行性能验证,并评价5种临床常用检测方法 .方法 按照美国CDC推荐的血清葡萄糖测定己糖激酶参考方法 的要求,建立参考方法 ;通过测定标准参考物质(SRM),以及参加国际临床化学与检验医学联合会(IFCC)主办的参考实验窒间的国际环形比对试验(ring-trial),来验证参考方法 的准确性;按照美国临床和实验室标准委员会(CLSI)EP9-A2试验方案,己糖激酶参考方法 作为比对方法 ,5种临床常用检测方法 作为待评方法 ,同时测定40份血清样品.结果 用己糖激酶参考方法 测定SRM965a,水平2和水平3与靶值的偏倚分别为0.93%、-0.23%;参加参考实验室国际比对,血清葡萄糖检测结果 在可接受范围内;5种常用检测方法 在医学决定点(Xc=6.11 mmol/L)预期偏差的95%可信区间在实验窜定义的可接受偏差(10%)范围内,也在生物学变异的可接受偏差(6.9%)范围内.结论 本室已复现并验证了血清葡萄糖测定己糖激酶参考方法 ;5种常用血清葡萄糖检测方法 的测定结果 与参考方法 的测定结果 有差异,但误差在临床可接受范围,不会影响临床检测结果 .     

Continuous-flow analysis for glucose with use of glucose dehydrogenase immobilized in glass tubes

We describe a method for determining glucose in serum with glucose dehydrogenase immobilized on the inner walls of glass tubes. The reactor was incorporated into a channel of a continuous-flow analyzer (the Technicon SMAC) and used daily for four weeks in routine analysis for serum glucose. During this period we tested the linearity, precision, accuracy, and durability of the reactor. Results correlated well (r = 0.9949) with those obtained by routine methods with free (nonimmobilized) glucose dehydrogenase. The method is shown to be practicable for use in the routine laboratory.     

Evaluating the clinical accuracy of two continuous glucose sensors using continuous glucose-error grid analysis

OBJECTIVE: To compare the clinical accuracy of two different continuous glucose sensors (CGS) during euglycemia and hypoglycemia using continuous glucose-error grid analysis (CG-EGA). RESEARCH DESIGN AND METHODS: FreeStyle Navigator (Abbott Laboratories, Alameda, CA) and MiniMed CGMS (Medtronic, Northridge, CA) CGSs were applied to the abdomens of 16 type 1 diabetic subjects (age 42 +/- 3 years) 12 h before the initiation of the study. Each system was calibrated according to the manufacturer's recommendations. Each subject underwent a hyperinsulinemic-euglycemic clamp (blood glucose goal 110 mg/dl) for 70-210 min followed by a 1-mg.dl(-1).min(-1) controlled reduction in blood glucose toward a nadir of 40 mg/dl. Arterialized blood glucose was determined every 5 min using a Beckman Glucose Analyzer (Fullerton, CA). CGS glucose recordings were matched to the reference blood glucose with 30-s precision, and rates of glucose change were calculated for 5-min intervals. CG-EGA was used to quantify the clinical accuracy of both systems by estimating combined point and rate accuracy of each system in the euglycemic (70-180 mg/dl) and hypoglycemic (<70 mg/dl) ranges. RESULTS: A total of 1,104 data pairs were recorded in the euglycemic range and 250 data pairs in the hypoglycemic range. Overall correlation between CGS and reference glucose was similar for both systems (Navigator, r = 0.84; CGMS, r = 0.79, NS). During euglycemia, both CGS systems had similar clinical accuracy (Navigator zones A + B, 88.8%; CGMS zones A + B, 89.3%, NS). However, during hypoglycemia, the Navigator was significantly more clinically accurate than the CGMS (zones A + B = 82.4 vs. 61.6%, Navigator and CGMS, respectively, P < 0.0005). CONCLUSIONS: CG-EGA is a helpful tool for evaluating and comparing the clinical accuracy of CGS systems in different blood glucose ranges. CG-EGA provides accuracy details beyond other methods of evaluation, including correlational analysis and the original EGA.     

Glucose and lactate concentration determination on single microsamples by Fourier-transform infrared spectroscopy

This study is the first to assess the analytic potential of Fourier-transform infrared (FT-IR) spectroscopy in determining exercise-induced metabolic changes, such as glucose and lactate serum concentrations, with single 50 microL blood microsamples. One-hundred ninety-eight capillary blood samples were taken at rest (rest serum) and after rowing exercises at different intensities (exercise serum) to obtain a wide range of lactate concentrations. A quantitative method is described with FT-IR spectroscopy involving only dilution and dessiccation of serum samples. Within serum spectra, an absorption band was strongly specific of glucose (1033 cm(-1)) that allowed the determination of its concentration (r = 0.97; P < .001 with reference values). Once we had substrated measured glucose absorption in serum spectra, one other absorption band seemed to be specific for lactate (1127 cm(-1)), which allowed the determination of the concentration of this metabolite (r = 0.96; P < .001 with reference values). The convenience of a capillary blood sampling with the strong accuracy of FT-IR measurements is of particular interest for medicinal and biologic concerns.     

不同类型标本及仪器对血糖检测结果的影响

目的探讨罗氏血糖仪与全自动生化分析仪检测不同类型标本血糖水平的差异。方法收集2017年2-5月于南京市栖霞区妇幼保健院就诊患者及体检者的末梢血及静脉血标本104例。比较罗氏血糖仪检测的末梢血(末梢血POCT组)、静脉全血(全血POCT组)、静脉血浆(血浆POCT组)、静脉血清(血清POCT组)和全自动生化分析仪检测的静脉血浆(血浆生化仪组)、静脉血清(血清生化仪组)的血糖水平;验证罗氏血糖仪的精密度及线性范围。结果3台罗氏血糖仪的批内CV和批间CV均小于7.5%,符合判定标准。罗氏血糖仪检测的静脉全血血糖水平在1.1~24.4 mmol/L呈线性,R 2>0.95;静脉血清血糖水平在0.6~25.3 mmol/L呈线性,R 2>0.95,均符合线性要求。血糖水平<6 mmol/L的检测结果中,全血POCT组血糖水平低于其余各组(P<0.05);血糖水平为6~10 mmol/L的检测结果中,全血POCT组血糖水平低于血浆POCT组、血清POCT组、血浆生化仪组及血清生化仪组(P<0.05)。各组检测的血糖水平两两之间均具有显著相关性(r>0.99,P<0.05)。结论罗氏血糖仪检测精密度高,具有良好的线性,末梢血、静脉血浆、静脉血清等标本在血糖仪上的检测结果与全自动生化分析仪检测结果具有较好的可比性;罗氏血糖仪检测静脉全血时需进行一定程度的校正以保证结果的准确性。     

同位素稀释液相色谱串联质谱法测定血清葡萄糖

目的 建立一种使用同位素稀释液相色谱串联质谱法(ID-LC/MS/MS)测定血清葡萄糖的候选参考方法.方法 以[~(13)C_6]葡萄糖为内标,用重量法准确地与血清混合,除去蛋白后在碱性条件下与1-苯基-3-甲基-5-吡唑酮反应,用LC/MS/MS测定葡萄糖和内标衍生产物,以包括法定量.结果 血清葡萄糖测定的批内、批间和总变异系数的平均值分别为0.36%(范围0.28%-0.42%)、0.47%(范围0.20%-0.67%)和0.61%(范围0.42%-0.76%).加样回收试验的回收率范围为99.0%-100.9%.分析参考物质SRM 965a,测定结果与认定值的平均偏差为-0.20%(范围-0.39%-+0.11%).结论 建立了ID-LC/MS/MS法测定血清葡萄糖的方法,方法准确、精密、简便,可望作为血清葡萄糖测定的参考方法.     

Problems with the external quality assessment of accuracy of point of care devices (POCD) for blood glucose are independent of sample composition

This short article describes the results obtained in both internal and external quality assessment of point of care devices (POCD) for the monitoring of blood glucose. The results show that the use of synthetic, serum and whole blood matrices for the samples do not markedly change the inaccuracy of measurement. It is only possible to check precision of POC devices for glucose in external quality assessment (EQA) surveys for POC devices for blood glucose. The majority of devices used in point of care testing for blood glucose had acceptable (im)precision. The applications and limitations of the use of POC devices for blood glucose must be clearly defined before allowing their use in patient care programmes. Finally, the results confirm that the decision of the German Federal Medical Council (Bundes?rztekammer) to exclude POC devices from accuracy checks against a reference method procedure in national EQA surveys was correct, at least at the present time.     

Continuous improvement of medical test reliability using reference methods and matrix-corrected target values in proficiency testing schemes: Application to glucose assay

The reliability of biological tests is a major issue for patient care in terms of public health that involves high economic stakes. Reference methods, as well as regular external quality assessment schemes (EQAS), are needed to monitor the analytical performance of field methods. However, control material commutability is a major concern to assess method accuracy. To overcome material non-commutability, we investigated the possibility of using lyophilized serum samples together with a limited number of frozen serum samples to assign matrix-corrected target values, taking the example of glucose assays. Trueness of the current glucose assays was first measured against a primary reference method by using human frozen sera. Methods using hexokinase and glucose oxidase with spectroreflectometric detection proved very accurate, with bias ranging between -2.2% and +2.3%. Bias of methods using glucose oxidase with spectrophotometric detection was +4.5%. Matrix-related bias of the lyophilized materials was then determined and ranged from +2.5% to -14.4%. Matrix-corrected target values were assigned and used to assess trueness of 22 sub-peer groups. We demonstrated that matrix-corrected target values can be a valuable tool to assess field method accuracy in large scale surveys where commutable materials are not available in sufficient amount with acceptable costs.