Point-of-care testing (POCT): Current techniques and future perspectives

Point-of-care testing (POCT) is a laboratory-medicine discipline that is evolving rapidly in analytical scope and clinical application. In this review, we first describe the state of the art of medical-laboratory tests that can be performed near the patient. At present, POCT ranges from basic blood-glucose measurement to complex viscoelastic coagulation assays. POCT shortens the time to clinical decision-making about additional testing or therapy, as delays are no longer caused by transport and preparation of clinical samples, and biochemical-test results are rapidly available at the point of care. Improved medical outcome and lower costs may ensue.Recent, evolving technological advances enable the development of novel POCT instruments. We review the underlying analytical techniques. If new instruments are not yet in practical use, it is often hard to decide whether the underlying analytical principle has real advantage over former methods. However, future utilization of POCT also depends on health-care trends and new areas of application. But, even today, it can be assumed that, for certain applications, near-patient testing is a useful complement to conventional laboratory analyses.     

Importance of the choice of assumptions and models in the estimation of analytical quality specifications

The validity of any model depends on its ability to imagine the situation or problem to which it is applied. Further, the assumptions made in relation to the model are determining for the actual outcome. Within the field of clinical biochemistry a lot of models for analytical quality specifications, based on a variety of concepts and ’clinical settings’, have been proposed. A hierarchical structure for application of these approaches and models has been agreed on at several occasions in 1999. In this hierarchy, the highest rank is given to evaluation of analytical quality specifications based on ’clinical settings’/’clinical outcome’ models, followed by specifications based on biological variation and on ’clinicians opinions’. This contribution, deals with the problems of combining random and systematic errors and the implications of application of different models to a variety of clinical settings. Received: 1 June, 2002 Accepted: 17 July 2002 Presented at the European Conference on Quality in the Spotlight in Medical Laboratories, 7–9 October 2001, Antwerp, Belgium     

Point-of-care testing of proteins

Point-of-care testing (POCT) is a fast developing area in clinical diagnostics that is considered to be one of the main driving forces for the future in vitro diagnostic market. POCT means decentralized testing at the site of patient care. The most important POCT devices are handheld blood glucose sensors. In some of these sensors, after the application of less than 1 μl whole blood, the results are displayed in less than 10 s. For protein determination, the most commonly used devices are based on lateral flow technology. Although these devices are convenient to use, the results are often only qualitative or semiquantitative. The review will illuminate some of the current methods employed in POCT for proteins and will discuss the outlook for techniques (e.g., electrochemical immunosensors) that could have a great impact on future POCT of proteins.     

The clinical chemistry laboratory: current status, problems and diagnostic prospects

Although increased automation, advanced analytical techniques and sophisticated information technology have greatly improved the performance and quality in medical laboratory testing, several studies show that significant amounts of errors occur. Detailed analysis revealed that most of the errors occur in the preanalytical phase, while fewer errors occur in the intra- and post-analytical phase. The majority of errors are caused by wrong sampling or occur during transport to the laboratory. This review focuses on the analytical procedures in a large central laboratory. Possible problems are described by following samples from the patient to the laboratory and back. Finally, the advantages and disadvantages of point-of-care testing versus central laboratory are compared.     

多指标免疫分析的研究进展

免疫分析是临床上检测生理相关蛋白质指标的主要方法. 与单一指标的免疫分析相比, 临床体外诊断对多指标的生理相关蛋白质免疫分析有着更为广泛的需求. 通过在固相载体上完成免疫反应的非均相免疫分析具有灵敏度高的优点, 是当前多指标免疫分析的主流方法. 本文按照固相载体的不同, 对近年来的多指标免疫分析系统分别从技术原理、 实现方法、 各自特点等方面的研究进展进行综合阐述. 最后对比总结了不同系统的优势与不足, 并展望了微流控多指标免疫分析在即时检测领域的发展前景.     

Glucometer-based Ultra-sensitive BRAF V600E Mutation Detection Facilitated by Magnetic Nanochains and a Self-made Point-of-Care (POC) Device

We realized the user-friendly and field-based point-of-care detection on a self-made portable device with the aid of personal glucose meter (PGM) for single nucleotide polymorphisms (SNPs) of melanoma and colon cancer marker BRAF V600E with good sensitivity and selectivity by integrating the loop-mediated isothermal amplification (LAMP) reaction and the strand exchange signal transduction. The device is equipped with a rotating magnetic field as well as a heating element, under which the pre-added magnetic nanochains (MNCs) help to homogenize the reaction mixture and overcome the low diffusion efficacy of the reactant and the required temperature for different reactions can be met.     

Electrochemical Biosensors Based on Micro-fabricated Devices for Point-of-Care Testing: A Review

Point-of-care testing (POCT) is becoming a hot research topic that allows rapid, on-site, and non-professional measurements outside the central laboratory. The micro-fabricated devices prepared by various micro-machining technologies have shown the advantages of low reagent consumption, high-throughput samples, and wearability. This review presents the recent progress of electrochemical biosensors based on various micro-fabricated devices for POCT and the corresponding electrochemical techniques. Signal amplification strategies based on enzyme and nanotechnology are also illustrated for the more sensitive POCT applications of these micro-fabricated devices. Consequently, the trends and challenges of electrochemical biosensors based on micro-fabricated devices in POCT diagnosis are discussed.     

An Aptasensing Strategy Using the Phosphatase-mimic Nanozyme and pH Meter as Signal Readout

The demand for point-of-care testing (POCT) is growing dramatically, especially for district where health facilities are poorly staffed, poorly skilled and ill-equipped. As a commercialized portable device, pH meters can be used for detection of various targets, relying on bioactive enzymes. The nanozymes, as the alternative of the natural enzymes, have rarely been used for pH-metric POCT strategies. Herein, we developed an ultrasensitive pH-metric sandwich-type aptasensor based on the CeO₂ nanorods (CeO₂ NRs) as phosphatase-mimic and sodium monofluorophosphate (MFP) as catalytic substrate. Under optimal conditions, such strategy yields a detection limit of 1.17 nM with eligible selectivity for detecting thrombin.