苦味酸法和酶法测定血清肌酐室间质评现状分析

目的：探讨广东省计划生育机构实验室血清肌酐的检测质量现状。方法将肌酐室间质评（EQA）的质控品以邮寄的方式发放到各实验室,各实验室在规定时间内把检测数据、检测方法网告研究所。第一次室间质评有71家实验室使用苦味酸法,52家实验室使用酶法;第二次室间质评有37家实验室使用苦味酸法,64家实验室使用酶法,分析不同方法检测肌酐的数据结果。结果第一次室间质评苦味酸法组和酶法组能力比对检验（PT）合格率分别为57.46%和83.85%;第二次室间质评苦味酸法组和酶法组PT合格率分别为83.78%和97.19%。第二次室间质评使用苦味酸法检测肌酐的变异系数在6.67%～19.26%之间;酶法的变异系数在3.78%～11.43%之间,五个批号的质控品使用苦味酸法检测肌酐的结果与酶法均存在差异（P＜0.05）,其中低值质控苦味酸法检测结果高于酶法,偏差在9.82%～66.31%之间;高值质控苦味酸法检测结果低于酶法,偏差在4.30%～10.66%之间。结论酶法检测肌酐的质量明显优于苦味酸法。广东省计划生育机构实验室血清肌酐的检测质量有待提高。     

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。     

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。     

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.     

以参考方法实验室网络赋值的人血清为校准品改善酶学结果可比性的研究

目的应用参考方法实验室网络赋值的人源新鲜冰冻血清作为校准品,改善不同检测系统间酶学检测结果的可比性。方法由国内6家实验室组成的酶学参考方法实验室网络使用国际临床化学和检验医学联合会（IFCC）推荐的磷酸肌酸激酶（cK）、乳酸脱氢酶（LDH）参考测量程序为新鲜冰冻混合人血清赋值。再用此赋值血清（BCal）校准常规检测系统。各实验室在BCal校准前、后,重复检测BCal、水平1患者样本（S1）和水平2患者样本（S2）2次,记录并收集实验数据。结果使用BCal测得各检测系统的偏移,CK项目,69家实验室的62．3％的偏移小于或等于5％;95．7％的实验室的偏移小于或等于10％。LDH项目,68家实验室的52．9％的偏移小于或等于5％;92．6％的实验室的偏移小于或等于10％。Bcal校准后,2个水平患者样本CK项目系统间cV从5．15％和5．98％下降至1．93％和1．81％;LDH项目系统间cV从5．86％和5．50％下降至3．39％和3．53％。依医院级别分别统计的数据显示：校准后,三级、二级医院CK、LDH的室间cV均有明显降低,且两者无明显差异。两组均值也较校准前更趋接近。少数封闭的检测系统BCal检测结果显示：CK、LDH各系统的偏移分别为-7．O％～8．8％和-21．9％～12．7％,系统间CV分别为5．18％和11．30％。结论应用参考方法实验室网络赋值的新鲜冰冻人源血清做校准品,可在相当程度上改善酶学检验结果的可比性,并确保结果溯源至参考方法。对于少数不适用的封闭系统,应制定相应的正确度判定标准,并敦促生产厂家予以改进。     

北京市13家医院31套血清肌酐检测系统测定结果的比对调查及分析

目的了解北京市部分医院临床实验室血清肌酐检测的变异。方法以现场调查的方式向参加调查的13家实验室（31套检测系统）发放添加不同纯度肌酐标准物质的冰冻混合人血清样本8支（肌酐浓度80—1000μmol／L），具不同浓度肌酐的患者冰冻混合血清样本8支，按照各实验室标准操作程序测定肌酐。结果对于添加不同纯度肌酐标准物质的冰冻混合人血清样本，实验室间各检测系统肌酐测定结果的总CV为5．74％-9．68％，Beckman封闭检测系统测定结果的CV为2．64％～5．70％，碱性苦味酸动力学法开放检测系统的CV为5．96％-9．97％，酶法的CV为1．13％～8．95％；对于患者混合血清样本，总CV为5．90％～11．69％，Beckman封闭检测系统的CV为2．53％-9．69％，碱性苦味酸动力学法开放系统的CV为5．92％～10．11％，酶法的CV为1．23％-10．30％。与Beckman封闭检测系统测定结果相比，Dade检测系统（采用碱性苦味酸动力学法）测定所有血清肌酐结果的偏差为-5．99％--0．35％，对于除Dade检测系统外的采用碱性苦味酸动力学法的其他检测系统，当血清肌酐浓度〈200μmol／L时，测定结果偏高，且随肌酐浓度降低，正偏差增大，最大为11．85％，而在血清肌酐浓度〉200μmol／L时，显示负偏差，最大为-8．45％；采用酶法的所有检测系统测定结果均为负偏差，最大可达到-8．88％。结论实验室间血清肌酐测定结果的变异较大，封闭检测系统测定结果的可比性好，开放检测系统测定结果可比性较差，酶法检测系统测定结果系统偏低。肌酐测定的标准化亟待解决。     

我国肌酐检测系统性能分析

目的研究我国肌酐检测系统的检测性能。方法通过向全国1 402家实验室发放5个不同浓度批次的质评物,进行肌酐检测的实验室室间调查,同时收集各实验室2011年5月肌酐室内质量控制(IQC)信息,按照2种检测方法(苦味酸法和酶法)和11套检测系统分组分析。计算各检测系统室间质量评价(EQA)结果,剔除离群值后的均值(x珋)、标准差(s)、变异系数(CV)。以1/3允许总误差(TEa)和基于生物学变异的质量规范判断各检测系统的不精密度水平。采用各实验室EQA的平均偏差作为偏倚估计,IQC累积CV作为不精密度估计,计算各实验室的西格玛(σ)水平。结果 EQA结果分析中,苦味酸法组CV范围为1.03%～18.23%,酶法组为1.50%～8.08%。苦味酸法组中Beckman检测系统实验室间的变异情况较其他系统好,Beckman UniCel系列检测系统CV范围为3.13%～4.90%。酶法组中以HITACHI系列(Roche)检测系统的变异情况优于其余各组,CV为1.50%～3.00%。IQC结果分析中,80%以上的实验室通过1/3 TEa的质量规范,70%以上的实验室通过基于生物学变异最低质量规范。σ水平分析中,σ度量值>6的实验室酶法组约43%,苦味酸法组约23%。结论肌酐不同检测系统实验室间变异情况酶法组优于苦味酸法组,多数检测系统的不精密度水平满足生物学变异的最低标准,酶法组的σ水平优于苦味酸法组。我国实验室肌酐的检测性能还有待于进一步提高。     

总蛋白改良参考方法的建立及其用于临床检测结果的溯源性研究

目的建立测量总蛋白(TP)参考方法,评价不同实验室TP测定结果的溯源性。方法参照美国疾病控制与预防中心推荐的参考方法及相关文件,建立37℃温浴10min的总蛋白参考方法。根据美国临床实验室标准化协会系列文件对方法的精密度、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21家实验室,比较校准前、后赋值血清校准品、血清样本测定结果间的偏移,进行检验结果的可比性评价。结果改良参考方法的精密度评价样本浓度为55.48、88.68g/L的CV分别为0.56%、1.23%,标准参考物质909C与靶值的偏移为1.76%,分析测量范围上限128.69g/L。与参考方法测量结果比较,赋值血清校准品校准前平均偏移为6.38%,校准后降为1.86%,样本血清1、2校准前偏移分别为6.04%和8.71%,校准后降为-1.61%、-0.13%。结论改良的双缩脲法测量TP方法性能好,应用参考方法对新鲜血清进行赋值能够实现不同检测系统结果的溯源性。     

两种不同方法检测血清肌酐结果的比较

目的探讨苦味酸法和酶法检测血清肌酐水平的差异。方法用酶法和苦味酸法分别检测136份血清标本肌酐的水平,以酶法检测的值分为四组。结果1组苦味酸法值高于酶法值(P<0.01);2、3组两种方法测得值基本相符(P>0.05);4组苦味酸法值低于酶法值(P<0.01)。结论苦味酸法适应范围窄,干扰多;酶法适应范围宽,特异性强,干扰小。不同测定方法应建立不同参考值。     

临床化学常规项目检测结果的可比性调查

目的 探讨临床化学常规项目检验结果的室间可比性.方法 用新鲜混合人血清,对44家医院进行17项临床化学检验的现场调查.结果 在常规条件下,不同项目的室间平均变异系数(CV%)为9.52%;各实验室用各自的校准品校准后,室间平均CV%为9.22%;用同一批号的cfas校准品校准后,室间平均CV%为9.44%;用赋值的新鲜混合人血清校准后,室间平均CV%为4.10%.结论 用赋值的新鲜混合人血清校准实验室的日常检测工作,可明显提高检验结果的室间可比性.     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

Dissociable correlates of two classes of retrieval processing in prefrontal cortex

Although substantial evidence suggests that the prefrontal cortex (PFC) implements processes that are critical for accurate episodic memory judgments, the specific roles of different PFC subregions remain unclear. Here, we used event-related functional magnetic resonance imaging to distinguish between prefrontal activity related to operations that (1) influence processing of retrieval cues based on current task demands, or (2) are involved in monitoring the outputs of retrieval. Fourteen participants studied auditory words spoken by a male or female speaker and completed memory tests in which the stimuli were unstudied foil words and studied words spoken by either the same speaker at study, or the alternate speaker. On "general" test trials, participants were to determine whether each word was studied, regardless of the voice of the speaker, whereas on "specific" test trials, participants were to additionally distinguish between studied words that were spoken in the same voice or a different voice at study. Thus, on specific test trials, participants were explicitly required to attend to voice information in order to evaluate each test item. Anterior (right BA 10), dorsolateral prefrontal (right BA 46), and inferior frontal (bilateral BA 47/12) regions were more active during specific than during general trials. Activation in anterior and dorsolateral PFC was enhanced during specific test trials even in response to unstudied items, suggesting that activation in these regions was related to the differential processing of retrieval cues in the two tasks. In contrast, differences between specific and general test trials in inferior frontal regions (bilateral BA 47/12) were seen only for studied items, suggesting a role for these regions in post-retrieval monitoring processes. Results from this study are consistent with the idea that different PFC subregions implement distinct, but complementary processes that collectively support accurate episodic memory judgments.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

Clinical Pharmacokinetics of Morphine

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.