Electrochemical biosensors for point-of-care testing

Point-of-care testing(POCT)is the practice of diagnosing and monitoring diseases where the patient is located,as opposed to traditional treatment conducted solely in a medical laboratory or other clinical setting.POCT has been less common in the recent past due to a lack of portable medical devices capable of facilitating effective medical testing.However,recent growth has occurred in this field due to advances in diagnostic technologies,device miniaturization,and progress in wearable electronics.Among these developments,electrochemical sensors have attracted interest in the POCT field due to their high sensitivity,compact size,and affordability.They are used in various applications,from disease diagnosis to health status monitoring.In this paper we explore recent advancements in electrochemical sensors,the methods of fabricating them,and the various types of sensing mechanisms that can be used.Furthermore,we delve into methods for immobilizing specific biorecognition elements,including enzymes,antibodies,and aptamers,onto electrode surfaces and how these sensors are used in real-world POCT settings.

Process of Designing Robust, Dependable, Safe and Secure Software for Medical Devices: Point of Care Testing Device as a Case Study

This paper presents a holistic methodology for the design of medical device software, which encompasses of a new way of eliciting requirements, system design process, security design guideline, cloud architecture design, combinatorial testing process and agile project management. The paper uses point of care diagnostics as a case study where the software and hardware must be robust, reliable to provide accurate diagnosis of diseases. As software and software intensive systems are becoming increasingly complex, the impact of failures can lead to significant property damage, or damage to the environment. Within the medical diagnostic device software domain such failures can result in misdiagnosis leading to clinical complications and in some cases death. Software faults can arise due to the interaction among the software, the hardware, third party software and the operating environment. Unanticipated environmental changes and latent coding errors lead to operation faults despite of the fact that usually a significant effort has been expended in the design, verification and validation of the software system. It is becoming increasingly more apparent that one needs to adopt different approaches, which will guarantee that a complex software system meets all safety, security, and reliability requirements, in addition to complying with standards such as IEC 62304. There are many initiatives taken to develop safety and security critical systems, at different development phases and in different contexts, ranging from infrastructure design to device design. Different approaches are implemented to design error free software for safety critical systems. By adopting the strategies and processes presented in this paper one can overcome the challenges in developing error free software for medical devices (or safety critical systems).

Point-of-Care Testing Using Three Dimensional Optical Biosensor Based on Microfluidic Technology

We have presented a three dimensional optical protein chip that fulfills the demanding for point-of-care diagnostics in terms of ease-of-use (one step assay), miniaturization (5 μl). The artful combination of magnetic nanoparticles on chip and total internal reflection imaging (TIRI) technology permits the sensitive and rapid detection of hs-CRP (high-sensitivity C-reactive protein). The whole test was complete within 10 min using “all in one step” assay with a limit of detection of 0.1 ng/mL hs-CRP. The measuring range for hs-CRP could be extended to 10 ng/mL. The chip can also be used to detect more parameters in blood samples.

Point-of-Care Testing vs. Laboratory Testing during High Patient Volume Situations

Introduction: Our aim was to determine what patient volume, if any, in-laboratory testing provides results faster than Point-of-Care-Testing (POCT). Methods: To evaluate POCT effectiveness during high volume situations, POCT was compared to in-laboratory testing during busy periods with large numbers of patients. Our setting was an urban level 1 trauma center with an academic emergency medicine department (ED) and annual patient volume of 70,000. Patients seen requiring laboratory testing during peak volume between 11 a.m. and 7 p.m. were enrolled over a five-week period. One tube of blood was sent to the laboratory and the other tube was run in the ED using POCT. Turnaround time was recorded as time from when the tube was received to when the result was available. We also completed a time-motion study to assess the number of POCT machines that would be needed to process the entire average hourly hospital laboratory volume. Results: We collected 539 hematology and chemistry specimens. The POCT group was significantly faster than in-laboratory testing, with mean POCT [complete blood count (CBC) and chemistry] 3.5 minutes compared to in-laboratory CBC test time of 30.9 minutes and chemistry test time of 55 minutes. As the volume of samples peaked, there was a slight but insignificant decrease in POCT turnaround time. If POCT was used to process the entire average hospital laboratory volume which approached 54 samples an hour, 3 POCT machines would be necessary to maintain turnaround times. Conclusion: Even during ED high volume situations, POCT provided results significantly faster than in-laboratory testing.

Evaluation of a Plasma hCG Method for Point of Care Testing with the Aim of Shortening Test-Turnaround-Times

Objective: To examine the correlation between plasma hCG results obtained with the new i-STAT&reg hCG point of care test with those concomitantly obtained from the central hospital laboratory utilizing the same patient samples. Methods: Prospective cross-sectional laboratory test evaluation. We compared plasma hCG results obtained with the i-STAT&reg hCG test (Abbott Point of Care, Princeton, NJ, USA) with Architect Ci8200 (Abbott Laboratories, Abbott Park, IL, USA). We also calculated the total coefficient of variation (CV) for the i-STAT&reg method. Results: The two methods showed a good linear correlation (R2 = 0.994;slope 1.03) and CV for the i-STAT&reg method was 2.1% - 5.2%. Conclusion: We suggest that the i-STAT&reg hCG blood assay could be used as a complement to urine hCG assays in clinical situations when rapid test results are needed and urine is not available.

Security Framework for Managing Data Security within Point of Care Tests

Point of Care (PoC) devices and systems can be categorized into three broad classes (CAT 1, CAT 2, and CAT 3) based on the context of operation and usage. In this paper, the categories are defined to address certain usage models of the PoC device. PoC devices that are used for PoC testing and diagnostic applications are defined CAT 1 devices;PoC devices that are used for patient monitoring are defined as CAT 2 devices (PoCM);PoC devices that are used for as interfacing with other devices are defined as CAT 3 devices (PoCI). The PoCI devices provide an interface gateway for collecting and aggregating data from other medical devices. In all categories, data security is an important aspect. This paper presents a security framework concept, which is applicable for all of the classes of PoC operation. It outlines the concepts and security framework for preventing security challenges in unauthorized access to data, unintended data flow, and data tampering during communication between system entities, the user, and the PoC system. The security framework includes secure layering of basic PoC system architecture, protection of PoC devices in the context of application and network. Developing the security framework is taken into account of a thread model of the PoC system. A proposal for a low-level protocol is discussed. This protocol is independent of communications technologies, and it is elaborated in relation to providing security. An algorithm that can be used to overcome the threat challenges has been shown using the elements in the protocol. The paper further discusses the vulnerability scanning process for the PoC system interconnected network. The paper also presents a four-step process of authentication and authorization framework for providing the security for the PoC system. Finally, the paper concludes with the machine to machine (M2M) security viewpoint and discusses the key stakeholders within an actual deployment of the PoC system and its security challenges.

A Point-of-Care Test System for Biochemical Blood Analysis Based on ADUC824

A point-of-care test system has been studied in this paper.It was used to determine substances in blood such as Hemoglobin (HB),Aspartate Aminotransferase (AST),Creatine Kinase (CK) and so on.Based on the principle of amperometric determination,the research on detecting weak current signals was carried on.At the same time as to the weak signals (nA level),magnifying,sampling and processing the signals were also studied.Controlled by ADUC824 and assisted by other units, every substance could be determined automatically and rapidly integrated with the corresponding biosensor.In the experiment, the minimum detectable current of the instrument (YT2005-1) is 0.2 nA.With regard to the 1 nA which the experiment demanded,it could be up to the mustard.And the system can provide results in 180 s with a long term stability.

14台POCT血气分析仪与中心实验室检测结果的一致性分析

目的分析14台床旁检测(POCT)血气分析仪和中心实验室血气分析仪检测结果的一致性。方法采用中心实验室血气分析仪及14台POCT血气分析仪分别检测3个浓度水平质控品,每天检测2次,连续检测4 d,共24次,根据检测结果计算pH、动脉血二氧化碳分压(PCO_(2))、动脉血氧分压(PO_(2))、K^(+)、Na^(+)、Cl^(-)、Ca^(2+)的均值、标准差和变异系数等;计算14台POCT血气分析仪检测结果与中心实验室检测结果的偏倚及偏倚率;应用ANOVA检验、Passing-Bablok回归分析对14台POCT血气分析仪与中心实验室检测结果一致性进行分析评价。结果14台POCT血气分析仪各比对项目检测结果的变异系数均小于生产商声明的性能范围。14台POCT血气分析各比对项目的检测结果与中心实验室的偏倚均小于国家卫生健康委员会临床检验中心室间质量评价标准。14台POCT台血气分析各比对项目的检测结果比较,差异均无统计学意义(P>0.05)。14台POCT血气分析仪检测结果与中心实验室pH值、PCO_(2)、PO_(2)、K^(+)、Na^(+)、Cl^(-)、Ca^(2+)检测结果模拟回归方程的截距和斜率均在95%置信区间,且P>0.05,与中心实验室检测结果具有高度的一致性。结论14台POCT血气分析仪具有良好的精密度,且14台POCT血气分析仪之间及与中心实验室间均具有较好的一致性。

Assessment of platelet function: Laboratory and point-of-care methods

In the event of blood vessel damage, human platelets are promptly recruited on the site of injury and, after their adhesion, activation and aggregation, prevent blood loss with the formation of a clot. The consequence of abnormal regulation can be either hemorrhage or the development of thrombosis. Qualitative and/or quantitative defects in platelets promote bleeding, whereas the residual reactivity of platelets, despite antiplatelet therapies, play an important role in promoting arterial thrombotic complications. Platelet function is traditionally assessed to investigate the origin of a bleeding syndrome, to predict the risk of bleeding prior surgery or during pregnancy or to monitor the efficacy of antiplatelet therapy in thrombotic syndromes that, now, can be considered a new discipline. "Old" platelet function laboratory tests such as the evaluation of bleeding time and the platelet aggregation analysis inplatelet-rich plasma are traditionally utilized to aid in the diagnosis and management of patients with platelet and hemostatic disorders and used as diagnostic tools both in bleeding and thrombotic diathesis in specialized laboratories. Now, new and renewed automated systems have been introduced to provide a simple, rapid assessment of platelet function including point of care methods. These new methodologies are also suitable for being used in non-specialized laboratories and in critical area for assessing platelet function in whole blood without the requirement of sample processing. Some of these methods are also beginning to be incorporated into routine clinical use and can be utilized as not only as first panel for the diagnosis of platelet dysfunction, but also for monitoring anti-platelet therapy and to potentially assess risk of both bleeding and/or thrombosis.

2018-2023年重庆市肌钙蛋白POCT室间质量评价结果分析

目的分析2018-2023年重庆市肌钙蛋白即时检测(POCT)室间质量评价(EQA)结果,了解重庆市肌钙蛋白POCT检测现状,为提高重庆市肌钙蛋白POCT检测能力提供依据。方法收集2018-2023年参加重庆市临床检验中心肌钙蛋白POCT EQA实验室结果,并进行统计分析。结果2018-2023年参加重庆市肌钙蛋白POCT EQA的实验室数从36家增加至88家,所使用的仪器品牌分组数从无增加至8个,每批次实验室合格率从最低26.32%增加至最高89.77%,但仍存在各仪器品牌分组靶值差异较大的现象,2023年各批号分组靶值的变异系数为44.72%~105.69%。结论重庆市肌钙蛋白POCT EQA参加率和检测水平尚有待提高,需持续将肌钙蛋白POCT纳入EQA计划,以定期监测全市范围内该项目的检测质量,为临床诊疗提供快速、可靠的保障。

两种分子POCT产品在流感病毒核酸快速诊断中的应用评价

目的评估两款分子即时检验(POCT)产品在临床甲型流感病毒(Flu A)、乙型流感病毒(Flu B)检测中的应用价值,并初步评估外周血感染相关指标在流感病毒感染中的诊断价值。方法选取2019年11月1日至2023年6月30日于该院就诊的、有流感样症状的流感疑似患者491例纳入研究并收集其口咽拭子,分别用逆转录实时荧光定量聚合酶链反应(RT-qPCR)和两种分子POCT产品(Xpert TM Xpress Flu/RSV和EasyNAT Flu Assay)进行检测。以RT-qPCR结果为标准将受试者分为Flu A阳性组、Flu B阳性组和阴性组(Flu A、Flu B检测均为阴性),分析并比较两种分子POCT产品的诊断性能及受试者外周血感染相关指标,评估这些指标对Flu A、Flu B临床诊断的价值。结果491例患者标本中,Xpert TM Xpress Flu/RSV检测Flu A的灵敏度为96.88%,特异度为99.75%,检测Flu B的灵敏度为100.00%,特异度为100.00%,EasyNAT Flu Assay检测Flu A的灵敏度为94.79%,特异度为96.81%,检测Flu B的灵敏度为100.00%,特异度为100.00%,两种分子POCT检测方法的一致性较高(Kappa值为0.974)。阴性组、Flu A阳性组和Flu B阳性组外周血中的C反应蛋白和血清淀粉样蛋白A水平比较差异无统计学意义(P>0.05),但阴性组白细胞计数较Flu A阳性组和Flu B阳性组高(P<0.01)。结论该文研究了两种典型的分子POCT产品,它们的灵敏度、特异度与RT-qPCR结果具有高度一致性。分子POCT产品具有灵活、快速等优势,对于目前临床诊疗水平的提高具有重要价值。分子检测手段同时联合外周血感染相关指标,有助于流感病毒感染性疾病的早期诊断。

芯片实验室技术在POCT上的最新进展

芯片实验室在临床诊断,特别是在床边诊断(POCT)检验领域具有重要作用。介绍了芯片实验室技术在POCT领域,尤其是近两年来在核酸、蛋白质及细胞检测等方面的最新研究进展,以及纳米技术和传统技术如免疫层析试纸条技术融合后,芯片实验室在POCT领域所显示出的优势。对芯片实验室技术未来在POCT领域的发展方向进行了讨论。

25台POCT血糖仪与全自动生化分析仪血糖测定结果比对分析

目的：定期监测全院25台床旁检验血糖仪（以下简称POCT血糖仪）检测结果与贝克曼生化分析仪血糖测定结果的一致性,全面了解医院各病区血糖测定值之间的差异。方法：挑选10位空腹血糖在3.34～23.4 mmol/L（生化分析仪血糖检测结果）的患者,分别抽取EDTA抗凝全血和未抗凝血。EDTA抗凝血在POCT血糖仪测定血糖;不抗凝血在贝克曼DXC800生化分析仪测定血清葡萄糖,每份样本测定3次,取均值。经比对,21台POCT血糖仪与生化分析仪测定值偏倚〈20%。对21台仪器按使用年限编号排序,按规则抽样5台,用卫生部POCT血糖室间质评物测定血糖,与卫生部临床检验中心室间质评回报结果的靶值比对,计算偏倚。结果：POCT血糖仪测定结果与生化分析仪测定结果比对,21台偏倚在1.1%～13.1%范围,4台仪器分别有3-4个浓度的测定值偏倚〉20%（偏倚b ias22%～25%）。21台POCT血糖仪测定值变异系数（CV%）为3.4%～8.5%。抽样的5台POCT血糖仪与卫生部临床检验中心POCT血糖室间质评靶值（以下简称＂靶值＂）的偏倚为0～11.4%。结论：25台POCT血糖仪中21台与生化分析仪血糖检测结果比对具有一致性,4台比对差异大。生化分析仪比POCT血糖仪检测结果偏高约7.2%-13.1%。抽样的5台POCT血糖仪与靶值之间的偏倚符合卫生部临床检验中心质评判定标准。

POCT血糖仪与全自动生化分析仪检测血葡萄糖结果对比分析

目的探讨POCT快速血糖仪与自动生化分析仪检测血糖结果的相关性及差异性,为临床提供参考。方法用5个浓度的质控品和患者标本在POCT血糖仪上进行检测,连续测试5d,计算变异系数(CV)。用POCT快速血糖仪和全自动生化分析仪对54例患者的末梢血和静脉血浆进行血糖检测,测得的数据用SPSS统计学软件进行分析,评价POCT血糖仪与全自动生化仪与测定结果的相关性。结果 5个浓度的质控品和患者标本在POCT血糖仪上所测结果的CV在2.6%～4.2%,低于厂家的声明,也符合国家对血糖检测系统的测量重复性要求(CV不超过7.5%)。雅培Optium Xceed血糖仪与全自动生化仪所测结果的相关系数(r)=0.974,相关性较好。结论雅培Optium Xceed血糖仪在精密度和准确度等方面均符合临床要求,其检测结果接近血浆葡萄糖检测结果。但是POCT血糖仪仅可用于患者空腹血糖的监测或血糖过筛实验,不能代替实验室血糖的检测结果作为确诊实验。

多台POCT血气分析仪比对方法的建立与分析

目的根据临床实验室标准化协会对仪器比对的要求和即时检验(POCT)血气分析仪的特点,建立基于质控数据的仪器比对方法。并采用建立的比对方法比较华西医院各临床科室和中心实验室23台血气分析仪检测结果的一致性。方法参照临床实验室标准化协会对仪器比对的要求,收集每台POCT血气分析仪连续30 d的室内质控结果,计算均值、标准差(s)和变异系数(CV)。要求每台POCT血气分析仪的CV<1/3允许总误差(TEa),并根据每台POCT血气分析仪的均值,计算均值的均值、s和CV;基于同型号血气分析仪分析同批号质控品的均值应一致的理论,以均值间的CV<1/2 TEa判断各血气分析仪检测结果一致。结果23台血气分析仪30 d pH值、二氧化碳分压[P(CO2)]和氧分压[P(O2)]3个水平质控结果的CV均<1/3 TEa(pH值TEa为0.54%,P(CO2)TEa为8.00%,P(O2)TEa为12.00%)。23台POCT血气分析仪pH值3个质控水平均值的CV分别为0.07、0.08、0.02,均<1/2 TEa;P(CO2)3个质控水平均值的CV分别为0.63、1.78、1.48,均<1/2 TEa;P(O2)3个质控水平均值的CV分别为2.88、1.90、0.95,均<1/2 TEa。结论华西医院23台POCT血气分析仪分析结果一致,建立的比对方法可满足实验室认可和三级甲等医院评审要求。

POCT血糖仪与全自动生化分析仪血糖检测结果的比对

目的:评价3款床旁检验(POCT)血糖仪的主要性能,了解其测定静脉全血葡萄糖与生化分析仪检测血浆葡萄糖结果的差异。方法:用质控液进行3款血糖仪精密度试验,选取53例临床标本分别用血糖仪测定抗凝全血葡萄糖和生化分析仪测定血浆葡萄糖,结果使用SPSS10.0统计软件进行统计分析。结果:3款血糖仪的批内CV分别为2.52%～2.78%、2.43%～3.55%、2.06%～2.15%,临床标本检测与生化仪(TBA120-FR)无显著性差异,回归方程分别为Y=0.954 1X+0.107 2、Y=0.953 6X+0.184 2、Y=0.958 9X+0.095 6。在医学决定水平处与比较检测系统比较差异小于5%。结论:POCT血糖仪经规范化操作和校准措施后,可以用于糖尿病的筛查及糖尿病患者的血糖监测。

POCT质量管理体系建设方案与成效分析

针对POCT质量管理系统缺陷问题,某三级医院建立了院内POCT质量管理体系,包括POCT管理架构、相关制度与流程、资质与授权、质量控制等方面。该体系专业性与科学管理并重,并借助信息化手段,实施完善的设备准入、结果报告与危急值管理。经实施,达到了流程简化、节约成本、平衡安全与便利的效果。下一步将对多种POCT检测项目进行信息化管理。

床旁即时检测（POCT）的质量控制

目的 加强床旁即时检测（POCT）质量控制和质量保证,获得优质报告结果.方法 通过分析影响POCT设备得出优质结果的分析前、分析中、分析后因素,同时进行内部质量控制和外部质量保证,得出优质的报告结果.结果 内部质量控制和外部质量保证保证了分析中的质量,对分析前和分析后影响POCT设备得出优质结果因素的分析可以加强分析前和分析后的质量控制.结论 内部质量控制和外部质量保证相结合,同时加强分析前和分析后质量控制可以保持POCT系统的质量,确保患者POCT检测结果的准确性.

POCT的临床应用及存在问题

随着免疫反应和分子生物技术的引进,即时检验(point of care testing,POCT)越来越受到人们的关注和重视。POCT临床应用广泛,主要用于儿科疾病、心血管疾病、感染性疾病、内分泌疾病、免疫性疾病、优生优育等方面的疾病的诊断及检测。但目前POCT还存在组织管理不够健全、质量控制体系不完善,检测成本偏高等问题。急需加强POCT临床应用的组织管理;加强非检验人员的操作培训;建立有效的质控措施;加强仪器功能的选择,做好仪器间的比对和日常实验过程中的室内质控,是POCT质量保证的重要手段。

两种POCT法测定血HCG的比对研究

目的分析金标斑点POCT法和免疫荧光POCT法检测血HCG的性能。方法将306例样本按照浓度从低到高分为6个组,第1组86例、第2组60例、第3组14例、第4组68例、第5组41例、第6组37例。用电化学发光法（ECLIA）、金标斑点POCT法、免疫荧光POCT法平行检测这6个组的血HCG浓度。以ECLIA法为标准对金标斑点POCT法和免疫荧光POCT法的结果进行配对资料的t检验。结果 （1）免疫荧光POCT法的比对：第1组样本,免疫荧光POCT法和ECLIA法的符合性好;2～5组样本,免疫荧光POCT法和ECLIA法的检测结果比较差异无统计学意义;第6组样本,免疫荧光POCT法和ECLIA法的检测结果的差异有统计学意义（P〈0.05）。（2）金标斑点POCT法的比对：1～2组样本,金标斑点POCT法和ECLIA法的符合性好;3～4组样本,金标斑点POCT法和ECLIA法的检测结果比较差异有统计学意义。结论免疫荧光POCT法能简便、快速、准确的检测血HCG的浓度,且检测的准确度比金标斑点POCT法好,检测的量程比金标斑点POCT法宽。免疫荧光POCT法更适合于目前各类医院血HCG的急诊检验。