No / The aim of this review was to examine whether the measurement of lactate in capillary blood samples using point-of-care handheld analysers corresponds sufficiently closely with arterial and venous whole-blood samples analysed by hospital central laboratory or blood gas analyser to be used interchangeably. A systematic search, informed by focused inclusion/exclusion criteria, was performed using multiple databases up to October 2015. A total of 65 articles were considered to have potential relevance and were evaluated in full text, of which ultimately five articles met all inclusion/exclusion criteria, and a final four were selected after data extraction and quality appraisal. All four studies found a predominantly upward bias in the measurement of lactate in capillary samples tested using a handheld point-of-care device over arterial or venous samples tested by laboratory methods or blood gas analyser. In terms of correlation, there was consensus between the studies that the strength of association between the two methods of measurement was statistically significant. Three studies directly examined the extent of agreement between point-of-care capillary lactate measurements and those of laboratory or blood gas analyser reference determined to ±2 standard deviations; 95% confidence intervals, and report contextually broad limits of agreement, identifying a potential for both over triage and, to a lesser extent, under triage. The findings of the review do not support interchangeable use of handheld fingertip point-of-care lactate measurement with laboratory or blood gas analyser methods in the identification of sepsis.

Yes / The COVID-19 pandemic placed the UK healthcare system under unprecedented pressure, and recovery will require whole-system investment in innovative, flexible and pragmatic solutions. Positioned at the heart of the healthcare system, ambulance services have been tasked with addressing avoidable hospital conveyance and reducing unnecessary emergency department and hospital attendances through the delivery of care closer to home. Having begun to implement models of care intended to increase ‘see and treat’ opportunities through greater numbers of senior clinical decision makers, emphasis has now been placed upon the use of remote clinical diagnostic tools and near-patient or point-of-care testing (POCT) to aid clinical decision making. In terms of POCT of blood samples obtained from patients in the pre-hospital setting, there is a paucity of evidence beyond its utility for measuring lactate and troponin in acute presentations such as sepsis, trauma and myocardial infarction, although potential exists for the analysis of a much wider panel of analytes beyond these isolated biomarkers. In addition, there is a relative dearth of evidence in respect of the practicalities of using POCT analysers in the pre-hospital setting. This single-site feasibility study aims to understand whether it is practical to use POCT for the analysis of patients’ blood samples in the urgent and emergency care pre-hospital setting, through descriptive data of POCT application and through qualitative focus group interviews of advanced practitioners (specialist paramedics) to inform the feasibility and design of a larger study. The primary outcome measure is focus group data measuring the experiences and perceived self-reported impact by specialist paramedics. Secondary outcome measures are number and type of cartridges used, number of successful and unsuccessful attempts in using the POCT analyser, length of time on scene, specialist paramedic recruitment and retention, number of patients who receive POCT, descriptive data of safe conveyance, patient demographics and presentations where POCT is applied and data quality. The study results will inform the design of a main trial if indicated. / The full-text of this article will be released for public view at the end of the publisher embargo on 1 Jun 2024.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2018-02-21T17:01:13Z No. of bitstreams: 2 Tese - Paulo de Tarso Garcia - 2017.pdf: 4177950 bytes, checksum: b76155aa4a091b54d3ad6a2ff6f1e6c6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2018-02-21T17:02:33Z (GMT) No. of bitstreams: 2 Tese - Paulo de Tarso Garcia - 2017.pdf: 4177950 bytes, checksum: b76155aa4a091b54d3ad6a2ff6f1e6c6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-02-21T17:02:33Z (GMT). No. of bitstreams: 2 Tese - Paulo de Tarso Garcia - 2017.pdf: 4177950 bytes, checksum: b76155aa4a091b54d3ad6a2ff6f1e6c6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-12-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This study describes the development of low cost colorimetric and electrochemical sensors aiming clinical and forensic applications. Firstly, a microfluidic paper-based analytical device (μPAD) was developed as colorimetric sensor for rapid estimation of post-mortem interval (PMI) on the crime scene using human vitreous-humour (VH) samples. Experimental parameters were optimized and the best conditions were: paper 1 CHR, 5 mm microzone diameter, 4 μL sample volume and 0.05 mol/L chromogen concentration. μPADs were coupled to colorimetric detection and the feasibility was demonstrated by Fe2+ determination in VH samples, in which the data were not statistically different from conventional technique (ICP-MS). It is important to highlight that Fe2+ levels were proportional to PMI. A color scale was also developed to help the forensic teams in order to estimate the PMI with a simple, quick and visual way. For electrochemical sensors, two different sensors were proposed to determine salivary α-amylase (sAA) levels in human saliva samples, aiming help in the diagnostic of pancreatitis and periodontitis. The first sensor based in a carbon screen-printed electrode (SPE) associated to amperometric detection. Experimental parameters were optimized and the best conditions were: 5 mmol L-1 NaOH (pH= 12), 20 min reaction time, 15 μL sAA volume and 0.5% (w/v) starch concentration. The feasibility of the sensor was demonstrated by sAA determination in five saliva samples (two from male donators and three from female individuals). The sAA concentrations ranged between 182.1 e 1117.1 U mL-1; once two female samples presented high sAA levels because the use of oral contraceptive. The other proposed electrochemical sensor was based in a Batch Injection Analysis with Amperometric Detection (BIA-AD) system using copper oxide (CuO) as working electrode (WE). Through experimental optimization was selected the potential that generate the best current signal. The WE obtained by a chemical/thermal treatment present good stability, once the relative standard deviation (RSD) value was 0.3%, which is ca. 75 fold lower than the RSD obtained with the electrochemical procedure to generate CuO in the electrode surface. The feasibility of the sensor was demonstrated by sAA determination in four human saliva samples. Was possible distinguish patients with and without periodontitis, obtaining thus a quick information about periodontal state of the patients. In general, the three proposed sensors in this study offered good precision, accuracy and specificity. Furthermore, the sensors are simple, portables, low cost and not requires none sophisticate instrumentation. Therefore, they present as promising alternatives to be used in point-of-care clinical and forensic analysis. / O trabalho descrito nesta tese demonstra o desenvolvimento de sensores colorimétricos e eletroquímicos de baixo custo, para aplicações nas áreas clínica e forense. Inicialmente, foi desenvolvido um dispositivo microfluídico de papel (μPAD, do inglês microfluidic paper-based analytical device) como sensor colorimétrico, visando a estimativa rápida do intervalo post-mortem (IPM) na cena do crime usando amostras de humor vítreo (HV) humano. Parâmetros experimentais foram otimizados e as melhores condições foram: papel tipo 1 CHR, microzona com 5 mm de diâmetro, volume de amostra de 4 μL e concentração de cromógeno de 0,05 mol/L. Os μPADs foram acoplados à detecção colorimétrica e a viabilidade foi demonstrada através da determinação dos níveis de Fe2+ em amostras de HV, onde os dados não diferiram estatisticamente da técnica convencional (ICP-MS). Vale ressaltar que os níveis de Fe2+ foram proporcionais ao IPM. Também foi desenvolvida uma escala de cor, para auxiliar as equipes forenses a estimar o IPM de maneira simples, rápida e visual. Em relação aos sensores eletroquímicos, foram propostos dois diferentes sensores para realizar a dosagem de α-amilase salivar (sAA, do inglês salivary α-amylase) em amostras de fluido oral humano, visando auxiliar no diagnóstico de doenças como pancreatite e periodontite. O primeiro sensor baseou-se em um eletrodo impresso (SPE, do inglês screen-printed electrode) de carbono associado a detecção amperométrica. Otimizou-se parâmetros experimentais e as melhores condições foram: concentração de NaOH igual a 5 mmol L-1 (pH= 12), tempo reacional de 20 min, volume de sAA de 15 μL e concentração de amido igual a 0,5% (m/v). A viabilidade do sensor foi demonstrada através da determinação de sAA em cinco amostras de fluido oral (duas de indivíduos do gênero masculino e três do gênero feminino). Os valores de concentração de sAA variaram entre 182,8 e 1117,1 U mL-1; sendo que duas amostras do gênero feminino exibiram elevados níveis de sAA devido ao uso de contraceptivo oral. O outro sensor eletroquímico proposto baseou-se em um sistema de análise por injeção em batelada com detecção amperométrica (BIA-AD, do inglês Batch Injection Analysis with Amperometric Detection) usando eletrodo de trabalho (ET) de óxido de cobre (CuO). Através de uma otimização experimental foi possível selecionar o potencial que fornece o melhor sinal de corrente. O ET obtido por um tratamento químico/térmico apresentou boa estabilidade, onde o valor de desvio padrão relativo (DPR) foi de 0,3%, que é cerca de 75 vezes menor do que o DPR obtido com o procedimento eletroquímico para gerar o CuO na superfície do eletrodo. A viabilidade do sensor foi demonstrada através da dosagem de sAA em quatro amostras de fluido oral humano. Foi possível diferenciar pacientes com e sem periodontite, obtendo assim uma informação rápida sobre a situação periodontal dos pacientes. De maneira geral, os três sensores propostos neste trabalho ofereceram boa precisão, exatidão e especificidade. Além disso, são simples, portáteis, de baixo custo e não requerem nenhuma instrumentação sofisticada. Sendo assim, se apresentam como alternativas promissoras para serem utilizados em análises clínicas e forenses no point-of-care.

Grâce aux technologies de la microfluidique (i.e. la manipulation d'un fluide dans un système ayant une dimension caractéristique sub-millimétrique), il est possible d'imaginer l'intégration de l'ensemble des fonctions ordinairement réalisées en laboratoire dans un système miniaturisé, réalisant ainsi un laboratoire sur puce. Cela peut ainsi permettre d'allier efficacité et bas-coût requis pour la réalisation de dispositif de diagnositcs médicaux utilisable en dehors d'infrastructure médicalisée, souvent appelés systèmes Point-of-Care. Pour la réalisation d'un tel dispositif, il semble important de concevoir l'intégration des différents composants du système d'une façon cohérente, et en prenant en compte l'ensemble des contraintes imposées par l'application finale ciblée. Le travail effectué au cours de cette thèse a ainsi été réalisé dans l'optique de proposer une réponse à cette problématique d'intégration dans le cadre du développement d'un système microfluidique de diagnostic Point-of-Care basé sur une réaction d'amplification d'ADN isotherme LAMP. Afin de pouvoir proposer un système bon marché et dont l'industrialisation est aisée, nous avons fait appel à l'utilisation du papier comme support et au thermoformage comme moyen de production. En effet à la fois l'industrie papetière et le procédé de thermoformage sont d'ores et déjà existant et proposent des fabrications en série. De plus, le faible coût du matériau et du procédé en question permettent d'envisager un dispositif final à bas-coût. Afin de pouvoir effectuer et détecter la réaction de LAMP la présence de fonctions actives telles qu'un chauffage et un outil de détection est nécessaire. Pour ces dernières, l'intégration a été réalisée par procédé sérigraphique. Le chauffage est effectué par effet Joule grâce au dépôt d'une couche d'encre conductrice à base de carbone. La détection est quant à elle faite par méthode potentiométrique, à l'aide d'électrode couverte de polyaniline. Il sera également montré que l'utilisation de ces méthodes de fabrication est pertinente en termes d'intégration car elles permettent une superposition des différentes fonctions actives, mais également leur intégration directement dans le système microfluidique. / Developments of microfluidics - the study of flows at the sub-millimetric dimensions - have made possible the integration of most of the macroscopic functions of laboratory fluidic systems in a miniaturized system, thus realizing a lab on a chip. This allows the conception of low cost, sensitive and efficient medical diagnostic device usable outside of a medical infrastructure. Such devices are called Point-of-Care (PoC) systems. The design and fabrication of such devices requires an elaborated and coherent integration that takes into account all the constraints imposed by the targeted final application.The work reported here, and performed during the PhD internship, is focused on the study of the concept and development of the integration of a PoC device based on the isothermal LAMP (Loop mediated AMPlification) reaction for the molecular analysis of DNA. In order to offer a cheap and easily industrialized system, we investigate the use of paper as the chip material and thermoforming as the mean to build the channels. These two techniques are currently used in the industry and their adaptation to the fabrication of such devices is easy and low-cost. In order to perform a LAMP reaction, specific functions such as a heating and a detection system are required. The integration of these functions was carried out using screen printing technology. Heating is done by Joule effect using a layer of carbon-based conductive ink. Detection is performed by a potentiometric method, using polyaniline-covered electrodes. It is shown that this approach is compatible with integration when the screen-printing layers are superposed. Besides they can be printed before thermoforming, resulting in a highly integrated system.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-05-04T14:00:33Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE VERSÃO DEFINITIVA COM ARTIGO 2 (1).pdf: 3543569 bytes, checksum: 401f073227f2753f70b28b7a15be070e (MD5) / Made available in DSpace on 2017-05-04T14:00:33Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE VERSÃO DEFINITIVA COM ARTIGO 2 (1).pdf: 3543569 bytes, checksum: 401f073227f2753f70b28b7a15be070e (MD5) Previous issue date: 2016-03-02 / FACEPE / A infecção pelo vírus da Hepatite B (HBV) é considerada uma enfermidade de alta morbimortalidade, apresentando diagnóstico complexo e quadro de persistência, fatores que dificultam a detecção, terapêutica e cura. Relatos variados têm apontado os imunossensores como importantes ferramentas de auxílio no diagnóstico de doenças, definido como um dispositivo que converte respostas de eventos biológicos a partir da interação antígenoanticorpo em sinal elétrico. No presente estudo foram desenvolvidos biossensores para detecção de anticorpos contra o nucleocapsídeo do HBV (Anti-HBc) mais perene apresentado no diagnóstico da doença. Recentemente, o emprego de nanomateriais no desenvolvimento de tais dispositivos tem despertado interesse devido às propriedades destes materiais. Particularmente, os nanotubos de carbono (NTCs) têm oferecido aos imunossensores melhoria na condutividade, aumento na velocidade de transferência de carga, aumento da área eletródica com maior possibilidade de imobilização de biomoléculas. Nesta tese, foram empregados o ácido hialurônico e o náfion como suporte para forte interação com os NTC funcionalizados em eletrodos de carbono vítreo e de ouro fabricado sobre folha de acetato. Os dispositivos foram caracterizados por técnicas de imagem (microscopia de força atômica) e eletroquímicas (voltametrias de onda quadrada e cíclica), as quais demonstraram a estabilidade da plataforma, imobilização eficaz e sensibilidade. O primeiro protótipo em eletrodos de carbono vítreo modificado com filme de ácido hialurônico associado a nanotubos funcionalizados apresentou resposta linear de 1 a 6ng/ml com limite de detcção de 0,03ng/ml. No segundo protótipo com eletrodos impressos de ouro modificado com filme etanólico de náfion associado a nanotubos funcionalizados, o imunossensor apresentou resposta linear de 0,5 até 2ng/ml, com limite de detecção de 0,15 ng/ml de anti-HBc. Os protótipos desenvolvidos apresentam-se como potenciais para diagóstico da HBV. / Infection with hepatitis B virus (HBV) is considered a high mortality disease, with complex diagnosis and persistence framework, factors that hinder detection, therapy and cure. various reports have pointed out the immunosensors as important aid tools in the diagnosis of disease, defined as a device that converts biological events of answers from the electrical signal in antigen-antibody interaction. In the present study biosensors have been developed for the detection of antibodies to the HBV nucleocapsid (anti-HBc) Perennial presented in the diagnosis of disease. Recently, the use of nanomaterials in the development of such devices has aroused interest because of the properties of these materials. Particularly, carbon nanotubes (CNTs) have offered immunosensors improvement in conductivity, increased charge transfer speed, increased electrodic area with the highest possibility of immobilization of biomolecules. In this thesis, we employed hyaluronic acid and nafion as support for strong interaction with the NTC functionalized glassy carbon electrodes and manufactured gold on acetate sheet. The devices were characterized by imaging techniques (atomic force microscopy) and electrochemical (cyclic and square wave voltammetry), which demonstrated the platform stability, effective restraint and sensitivity. The first prototype on glassy carbon electrode modified with hyaluronic acid film associated with functionalized nanotubes showed a linear response of 1 to 6ng/ ml with detction limit 0,03ng / ml. In the second prototype printed gold electrodes modified with ethanolic nafion film associated with functionalized nanotubes, the immunosensor showed a linear response of 0.5 to 2 ng / ml, the detection limit of 0.15 ng / ml of anti-HBc. The developed prototype is present as diagnostic potential for HBV.

Real-time, bedside observation of patient clotting is essential in various surgeries in the operating room (OR), but specifically during cardiac surgeries. The objective of this thesis is to design and test a new piezoelectric device that can be used for viscoelasticity measurement with time as a Point of Care (POC) test. Slow turnaround times (TAT) of current methods to monitor blood viscoelastic changes in patients have led to excessive bleeding and the need for blood transfusions in many situations (Despotis et al, 1997). This study shows that the phase shift produced by a resonator sensor can be related to the viscosity of a liquid. By monitoring a phase shift between an actuator and sensor pair, a numeric relationship can be generated and suffice as a calibration curve for each probe. At a calculated error averaging a maximum of 2%, and coefficient of determination and correlation coefficient exceeding 0.95, two probes have been tested in various glycerin solutions and prepared for whole blood experimentation. They have also been tested in varying temperatures to simulate effectiveness in a dynamic environment, similar to that of clotting whole blood.

Master of Science / Department of Biological & Agricultural Engineering / Mei He / Anemia affects about 25% of the world’s population and causes roughly 8% of all disability cases. The development of an affordable point-of-care (POC) device for detecting anemia could be a significant for individuals in underdeveloped countries trying to manage their anemia. The objective of this study was to design and fabricate a 3D printed, low cost microfluidic mixing chip that could be used for the diagnosis of anemia. Microfluidic mixing chips use capillary flow to move fluids without the aid of external power. With new developments in 3D printing technology, microfluidic devices can be fabricated quickly and inexpensively. This study designed and demonstrated a passive microfluidic mixing chip that used capillary force to mix blood and a hemoglobin detecting assay. A 3D computational fluid dynamic simulation model of the chip design showed 96% efficiency when mixing two fluids. The mixing chip was fabricated using a desktop 3D printer in one hour for less than $0.50. Blood samples used for the clinical validation were provided by The University of Kansas Medical Center Biospecimen Repository. During clinical validation, RGB (red, green, blue) values of the hemoglobin detection assay color change within the chip showed consistent and repeatable results, indicating the chip design works efficiently as a passive mixing device. The anemia detection assay tended to overestimate hemoglobin levels at lower values while underestimating them in higher values, showing the assay needs to go through more troubleshooting.

The disproportionate burden of infectious disease and lack of appropriate diagnostic tools in the developing world suggest that future health technology development efforts need to more effectively target these resource-limited settings. Microfluidic systems, like lab-on-a-chip technologies, offer the potential to miniaturize the large, complex processes performed in first-world laboratories onto a portable chip for use in remote settings. The problem with these systems is that they require equipment for fluidic handling and many other aspects of diagnostic assays such as sample preparation and analyte detection. The notion of “paperfluidics” has garnered much attention due to paper’s natural ability to wick fluids through capillary action without the need for pumps or other equipment. This and many other qualities of paper make it well suited for point-of-care diagnostics. Paper diagnostics have successfully been employed to detect the presence of antigens or small molecules in clinical samples; however, the detection of many disease targets relies on the much higher sensitivity and specificity of molecular diagnostics achieved via nucleic acid amplification tests (NAAT). The work presented in this dissertation describes the design and development of a paperfluidic sample-to-answer NAAT platform. Preliminary work focused on the development of separate NAAT modules for the extraction, amplification, and detection of nucleic acids from clinical samples directly within a paper matrix. A paper-based assay was developed, using Influenza A (H1N1) as a model system, for the extraction and purification of RNA directly from patient nasopharyngeal specimens, in situ isothermal amplification, and immediate lateral flow detection of amplified products. We then integrate these paper-based NAAT modules onto a single paperfluidic chip in a modular, foldable system that allows for fully-integrated fluidic handling from sample to answer. We showcase the full functionality of the chip by extracting, amplifying and detecting human papillomavirus (HPV) 16 DNA directly from crude cervical specimens in less than 1 hour, for early point-of-care detection of cervical cancer. The chip is made entirely of paper and adhesive sheets, making it low-cost, portable, and disposable, offering the potential for use in very remote settings and increasing access to screening to those most in need.

Point-of-care (POC) tests can improve the management of infectious diseases and clinical outcomes, through prompt diagnosis and appropriate delivery of treatments for preventable and treatable diseases, especially in resource-limited settings where health care infrastructure is weak, and access to quality and timely medical care is challenging. Microfluidics or lab-on-chip technology is appropriate for POC tests when general design constraints such as integration, portability, low power consumption, automation, and ruggedness are met. Although many POC tests have been designed for use in developed countries, they might not be readily transferable to resource-limited settings. These new technologies need to be accessible, affordable and practical to be implemented at resource-limited settings to save lives in developing countries. The overall goal of this dissertation is to develop microfluidic diagnostic devices which are practical and reliable for global health. We first focused on immunoassays, an important class of diagnostic tests which utilize antibodies to quantify host immunity or pathogen protein markers. We developed and evaluated a rapid, accurate, multiplexed, and portable microfluidic immunoassay for diagnosis of HIV and syphilis on hundreds of archived specimens (whole blood, plasma, and sera). Our assay exhibited performance equal to lab-based immunoassays in less than 20 minutes. In addition, our technique quantified signals using a handheld instrument, allowing for objective measurements as opposed to current rapid HIV tests which require subjective interpretation of band intensities. We further integrated three important off-chip processes in a diagnostic test - liquid handling, optical signal detection, and data communication – in a low-cost, versatile, handheld instrument capable of performing immunoassays on reagent-loaded (i.e. “ready-to-run”) cassettes at high analytical performance characteristic of ELISA but with the speed, portability and ease-of-use of a rapid test. We also evaluated this immunoassay device in Rwanda on archived samples and achieved analytical performance comparable to that of benchtop standards. To simplify the user interface and reduce the cost of the diagnostic device, we integrated our microfluidic immunoassay with a smartphone to replace computers or high-cost processors for diagnostic devices in low-resource settings. Our low-cost ($34), smartphone-supported device for a multiplexed immunoassay detected three antibody markers from HIV, treponemal- and non-treponemal syphilis from fingerstick whole blood simultaneously in 15 minutes. This device was designed to eliminate the number of manual steps, through the use of lyophilized secondary antibodies and anti-coagulant, preloaded reagents on cassette, and an automatic result readout. A step-by-step user guide was included on the smartphone to make the device simple enough to be used by an untrained operator. The analytical performance of the device was evaluated in Rwanda by local health care workers. We also accessed user experiences for improvement of the device in future. While immunoassays offer rapid and accurate diagnosis for infectious diseases, various infections cannot be confirmed using protein markers. Due to increasing clinical demand for detection of DNA and RNA signatures for diagnosis and monitoring of patients in resource-limited settings, we also explored how microfluidic and nanoparticle technologies can improve nucleic acid amplification test at the point of care. Nucleic acid tests are arguably some of the most challenging assays to develop due to additional steps required for sample pre-treatment (e.g. cell sorting, isolation, and lysis, as well as nucleic acid extraction), signal amplification (due to low physiological concentrations, target contamination, and instability) and product detection. Here we developed a sputum processor to isolate and lyse mycobacteria (M.smegmatis) from a more complex sample matrix, using magnetic beads-based target isolation to replace the need of a centrifuge or other complicated sample preparation technique. We also investigated a technique to detect Mycobacterium tuberculosis using multiplex polymerase chain reaction (PCR) and silver-gold amplification detection.

Point-of-care (POC) diagnostic technologies aim to expand access to traditional laboratory-based testing to near-patient settings. These settings can range from emergency or intensive care-units (ICUs) in the United States, to remote health posts in sub Saharan Africa. Differences in budget and infrastructure play a role in characterizing the wide array of possible “near patient” settings and must be taken into consideration in the engineering design process. In this dissertation we use translational engineering to develop practical and accessible microfluidic POC immunoassays for diverse settings, that include both provider and consumer facing applications. First, we examined Lyme Disease in the U.S., where existing diagnostic technologies face the challenge of rapid and accurate serodiagnosis in the face of largely non-specific clinical symptoms. We developed a multiplexed rapid test that could replicate enzyme-linked immunosorbent assay (ELISA) performance for Lyme Disease diagnosis. After screening candidate biomarkers, we evaluated performance of the multiplexed microfluidic test against ELISA using clinical serum samples and illustrated the potential to streamline current clinical algorithms requiring two immunoassays (ELISA and Western Blot) into one standalone test suitable for physician’s offices or urgent care clinics in the U.S. We also showed exploratory work towards a similar multiplexed test design for another bacterial spirochete infection, Leptospirosis. Next, we built on previous work towards a POC HIV-syphilis antenatal screening tool, to develop a smartphone-integrated, microfluidic assay for healthcare workers to use in low resource settings. The low-cost ($34), re-usable device (“smartphone dongle”) costs $34 to produce and provides results in 15 minutes. In this work, we focus on assay development efforts undertaken towards development of a fully integrated POC product suitable for deployment in the field, with practical considerations for the use of fingerstick blood, stability, scale-up and transport. We also streamlined the number of manual steps for end-user operation, through the use of lyophilized secondary antibodies, preloaded reagents on cassette, and an automatic result readout. While laboratory demonstration with clinical samples is important for initial characterization of POC devices, field evaluation reveals diagnostic performance under real-world conditions. We tested the device in the hands of minimally trained healthcare workers in Rwanda and saw comparable performance to other immunoassays run under field conditions. We also performed a follow-up pilot field study in Rwanda to evaluate the feasibility of the smartphone dongle platform for self-testing by patients/consumers in a low-resource setting, one of the most challenging use-cases for POC devices. Finally, we sought to integrate intellectual frameworks from behavioral research and user-experience (UX) design in creating a new framework for evaluation of consumer-facing microfluidic devices, specifically towards HIV home-testing in the U.S. While overall rates of HIV are decreasing in the U.S., the population of gay, bisexual and other men who have sex with men (MSM) are disproportionately affected. Self-testing products for sexually transmitted infection (STI) testing could address unmet needs for these target populations in both increasing access and frequency of testing, as well as integrating use with sexual partners for early diagnosis or even prevention. We worked with a cohort of MSMs at high risk for HIV/STI transmission in New York City, and performed for the first time, a structured assessment of completely naïve users interacting with a smartphone interfaced microfluidic diagnostic device (“SMARTtest”). We integrated UX design value model of device usability, credibility, accessibility and acceptability into our evaluation framework, which influence user’s information, knowledge, motivation and behavioral skills towards engaging with a prevention method (“IMB” model). Thus far, such frameworks have rarely been applied to other consumer health monitoring devices, including microfluidic POC devices. As the microfluidic field moves towards more field demonstrations of devices, more untrained and minimally trained users will have access to such tools. It is important to understand how they use devices, what the device failure points are and what the most relevant design features are to spur user adoption and meaningful usage. Underlying our work in creating accessible and practical POC immunoassay tools for infectious disease detection, is the illustration of the translational development roadmap from proof-of-concept assay development to field studies and user-based evaluations for intended end-use settings that range from U.S. based primary care clinics, rural health centers in low-resource settings as well as self-testing environments in both. Incorporating an understanding of the target use-case setting is critical in translating technologies for clinical use, whether in the infrastructure and services that are available, or end-user needs and constraints such as clinical workflow patterns, level of technical expertise and perceptions of usefulness and value. We show how user/use-case focused application of downstream translational engineering and testing informs upstream design choices and accelerates development of POC devices for real-world use. The sum of this work aims to illustrate tenets of translational engineering design and testing to advance insight into building POC products that are poised for greater adoption by target end users, whether they are health providers or consumers.