Smartphone-assisted point-of-care testing of nucleic acids based on hybridization chain reaction, magnetic beads, and gold nanorods etching

Colorimetric biosensors are simple but effective tools that are gaining popularity due to their ability to provide low-cost, rapid, and accurate detection for viruses like the Novel coronavirus, Influenza A, and Dengue virus, especially in point-of-care testing (POCT) and visual detection. In this study, a smartphone-assisted nucleic acid POCT was built using hybridization chain reaction (HCR), magnetic beads (MBs), and oxidized 3,3′,5,5′-tetramethylbenzidine (TMB2+)-mediated etching of gold nanorods (GNRs). The application of HCR without enzyme isothermal characteristics and MBs with easy separation, can quickly amplify nucleic acid signal and remove other reaction components. The blue shift of longitudinal localized surface plasmon resonance (LSPR) based on GNRs showed significant differences in etching color for different concentrations of target nucleic acid, which convert the signal into a visually semi-quantitative colorimetric result, achieving quantitative analysis with the color recognition software built into smartphones. This strategy, which only takes 40 min to detect and is two-thirds less time than the PCR, was successfully applied for the detection of the Dengue target sequence with a detection limit of 1.25 nM and exhibited excellent specificity for distinguishing single-base mutations, indicating broad application prospects in clinical laboratory diagnosis and enriching the research of nucleic acid POCT.

Acute or chronic? Failing left ventricle in a 34 year old

Submission content Introduction: An unusual case of a very young patient without previously known cardiac disease presenting with severe left ventricular failure, detected by a point of care echocardiogram. Main Body: A 34 year old previously well man was brought to hospital after seeing his general practitioner with one month of progressive shortness of breath on exertion. This began around the time the patient received his second covid-19 vaccination. He was sleeping in a chair as he was unable to lie flat. Abnormal observations led the GP to call an ambulance. In the emergency department, the patient required oxygen 5L/min to maintain SpO2 >94%, but he was not in respiratory distress at rest. Blood pressure was 92/53mmHg, mean 67mmHg. Point of care testing for COVID-19 was negative. He was alert, with warm peripheries. Lactate was 1.0mmol/L and he was producing more than 0.5ml/kg/hr of urine. There was no ankle swelling. ECG showed sinus tachycardia. He underwent CT pulmonary angiography which demonstrated no pulmonary embolus, but there was bilateral pulmonary edema. Troponin was 17ng/l, BNP was 2700pg/ml. Furosemide 40mg was given intravenously by the general medical team. Critical care outreach asked for an urgent intensivist review given the highly unusual diagnosis of pulmonary edema in a man of this age. An immediate FUSIC Heart scan identified a dilated left ventricle with end diastolic diameter 7cm and severe global systolic impairment. The right ventricle was not severely impaired, with TAPSE 18mm. There was no significant pericardial effusion. Multiple B lines and trace pulmonary effusions were identified at the lung bases. The patient was urgently discussed with the regional cardiac unit in case of further deterioration, basic images were shared via a cloud system. A potential diagnosis of vaccination-associated myocarditis was considered,1 but in view of the low troponin, the presentation was felt most likely to represent decompensated chronic dilated cardiomyopathy. The patient disclosed a family history of early cardiac death in males. Aggressive diuresis was commenced. The patient was admitted to a monitored bed given the potential risk of arrhythmia or further haemodynamic deterioration. Advice was given that in the event of worsening hypotension, fluids should not be administered but the cardiac centre should be contacted immediately. Formal echocardiography confirmed the POCUS findings, with ejection fraction <35%. He was initiated on ACE inhibitors and beta adrenergic blockade. His symptoms improved and he was able to return home and to work, and is currently undergoing further investigations to establish the etiology of his condition. Conclusion(s): Early echocardiography provided early evidence of a cardiac cause for the patient's presentation and highlighted the severity of the underlying pathology. This directed early aggressive diuresis and safety-netting by virtue of discussion with a tertiary cardiac centre whilst it was established whether this was an acute or decompensated chronic pathology. Ultrasound findings: PLAX, PSAX and A4Ch views demonstrating a severely dilated (7cm end diastolic diameter) left ventricle with global severe systolic impairment.

Point-of-Care Testing in Primary Care

Point-of-care testing (POCT) in pediatric primary care is essential for clinicians to make a timely and accurate diagnosis. The COVID-19 pandemic has highlighted the importance of timely and accurate testing strategies to correctly identify the etiology of upper and lower respiratory infections. Additionally, pediatric POCT continues to be important in rural and underserved communities where access to hospital laboratories may be less available. This chapter will focus on seven rapid tests: Group A streptococcus (GAS), influenza A & B, SARS-CoV-2 (COVID-19), human immunodeficiency virus (HIV), C-reactive protein (CRP), human chorionic gonadotropin (hCG), and hemoglobin A1c (HbA1c). © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.

Non-trauma uses of viscoelastic hemostatic assays in critical care: A narrative review and primer for pharmacists

Thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are point-of-care viscoelastic tests of whole blood that provide real-time analyses of coagulation. TEG and ROTEM are often used to guide blood product administration in the trauma and surgical settings. These tests are increasingly being explored for their use in other disease states encountered in critically ill patients and in the management of antithrombotic medications. As the medication experts, pharmacists should be familiar with how to interpret and apply viscoelastic tests to disease state and medication management. The purpose of this narrative review is to provide a primer for pharmacists on viscoelastic tests and their interpretation and to explore non-trauma indications for viscoelastic testing in critical care. Literature evaluating the use of TEG and ROTEM for patients with acute and chronic liver disease, ischemic and hemorrhagic stroke, myocardial infarction, cardiac arrest, coronavirus disease 2019, and extracorporeal membrane oxygenation are described. Current applications of viscoelastic tests by pharmacists and potential future roles of critical care pharmacists in expanding the use of viscoelastic tests are summarized.Copyright © 2023 The Authors. JACCP: Journal of the American College of Clinical Pharmacy published by Wiley Periodicals LLC on behalf of Pharmacotherapy Publications, Inc.

A 3D printed microfluidic PCR device towards detecting SARS-CoV-2

A 3D printed (3DP) microfluidic polymerase chain reaction (PCR) device was demonstrated by detecting synthetic SARSCoV-2 at 106 copies/μL. The microfluidic device was fabricated using stereolithography 3DP and had a reaction volume of ~22 nL. The microdevice showed PCR amplification with 85 base synthetic ssDNA targets and primers designed for a SARS-CoV-2-specific region. The device was 2.5 times faster compared to a qPCR instrument with >60,000 times smaller reagent volume. The 3DP microdevice is a promising technology to significantly reduce the manufacturing costs of microfluidic devices that could be used towards point-of-care applications. © 2023 SPIE.

Molecular Diagnostics on Smartphone

During the COVID-19 pandemic, point-of-care genetic testing (POCT) devices were used for on-time and on-site detection of the virus, which helped to prevent and control the spread of the pandemic. Smartphones, which are widely used electronic devices with many functions, have the potential to be used as a molecular diagnostic platform for universal healthcare monitoring. Several integrated diagnostics platforms for the real-time and end-point detection of COVID-19 were developed using the functions of smartphones, such as the operating system, power, sound, camera, data storage, and display. These platforms use the 5V output power of smartphones, which can be amplified to power a micro-capillary electrophoresis system or a thin-film heater, and the CMOS camera of smartphones can capture the color change during a colorimetric loop-mediated isothermal amplification test and detect fluorescence signals. Smartphones can also be used with self-written web-based apps to enable automatic and remote pathogen analysis on POCT platforms. Our lab developed a handheld micro-capillary electrophoresis device for end-point detection of SARS-CoV-2, as well as an integrated smartphone-based genetic analyzer for the qualitative and quantitative colorimetric detection of foodborne pathogens with the help of a custom mobile app. © 2023 SPIE.

Graphene-Based Electrochemical Nano-Biosensors for Detection of SARS-CoV-2

COVID-19, a viral respiratory illness, is caused by Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2), which was first identified in Wuhan, China, in 2019 and rapidly spread worldwide. Testing and isolation were essential to control the virus's transmission due to the severity of the disease. In this context, there is a global interest in the feasibility of employing nano-biosensors, especially those using graphene as a key material, for the real-time detection of the virus. The exceptional properties of graphene and the outstanding performance of nano-biosensors in identifying various viruses prompted a feasibility check on this technology. This paper focuses on the recent advances in using graphene-based electrochemical biosensors for sensing the SARS-CoV-2 virus. Specifically, it reviews various types of electrochemical biosensors, including amperometric, potentiometric, and impedimetric biosensors, and discusses the current challenges associated with biosensors for SARS-CoV-2 detection. The conclusion of this review discusses future directions in the field of electrochemical biosensors for SARS-CoV-2 detection, underscoring the importance of continued research and development in this domain.

Rapid and Low-Cost Detection of Human Corona Virus Using MEMS ATR-FTIR Spectroscopy

The conventional methods used for the diagnostics of viral infection are either expensive and time-consuming or not accurate enough and dependent on consumable reagents. In the presence of pandemics, a fast and reagent-free solution is needed for mass screening. Recently, the diagnosis of viral infections using infrared spectroscopy has been reported as a fast and low-cost method. In this work a fast and low-cost solution for corona viral detection using infrared spectroscopy based on a compact micro-electro-mechanical systems (MEMS) device and artificial intelligence (AI) suitable for mass deployment is presented. Among the different variants of the corona virus that can infect people, 229E is used in this study due to its low pathogeny. The MEMS ATR-FTIR device employs a 6 reflections ZnSe crystal interface working in the spectral range of 2200-7000 cm-1. The virus was propagated and maintained in a medium for long enough time then cell supernatant was collected and centrifuged. The supernatant was then transferred and titrated using plaque titration assay. Positive virus samples were prepared with a concentration of 105 PFU/mL. Positive and negative control samples were applied on the crystal surface, dried using a heating lamp and the spectrum was captured. Principal component analysis and logistic regression were used as simple AI techniques. A sensitivity of about 90 % and a specificity of about 80 % were obtained demonstrating the potential detection of the virus based on the MEMS FTIR device. © 2023 SPIE.

A Freehand 3D Ultrasound Carotid Scanning System for Point-of-Care Ultrasonography

Stroke is a leading cause of morbidity and mortality throughout the world. Three-dimensional ultrasound (3DUS) imaging was shown to be more sensitive to treatment effect and more accurate in stratifying stroke risk than two-dimensional ultrasound (2DUS) imaging. Point-of-care ultrasound screening (POCUS) is important for patients with limited mobility and at times when the patients have limited access to the ultrasound scanning room, such as in the COVID-19 era. We used an optical tracking system to track the 3D position and orientation of the 2DUS frames acquired by a commercial wireless ultrasound system and subsequently reconstructed a 3DUS image from these frames. The tracking requires spatial and temporal calibrations. Spatial calibration is required to determine the spatial relationship between the 2DUS machine and the tracking system. Spatial calibration was achieved by localizing the landmarks with known coordinates in a custom-designed Z-fiducial phantom in an 2DUS image. Temporal calibration is needed to synchronize the clock of the wireless ultrasound system and the optical tracking system so that position and orientation detected by the optical tracking system can be registered to the corresponding 2DUS frame. Temporal calibration was achieved by initiating the scanning by an abrupt motion that can be readily detected in both systems. This abrupt motion establishes a common reference time point, thereby synchronizing the clock in both systems. We demonstrated that the system can be used to visualize the three-dimensional structure of a carotid phantom. The error rate of the measurements is 2.3%. Upon in-vivo validation, this system will allow POCUS carotid scanning in clinical research and practices. © 2023 SPIE.

Electrochemical immunosensor for diagnosis of COVID-19

An immunosensor is a biosensor that detects antigen interactions using a particular antibody bound on the transducer's surface. These biosensors have high selectivity and sensitivity due to their interaction specificity. Owing to this characteristic, this type of sensor is attractive for several applications, especially in the medical area and bioanalysis. Among the types of immunosensors, electrochemical immunosensors have gained prominence due to their simplicity and portability, potentially enabling in situ detection as promising characteristic for analysis in emergency care. In this chapter, the potential of electrochemical immunosensors is presented, especially in applications related to clinical examinations and mainly in the diagnosis of SARS-CoV-2. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023. All rights reserved.

Smart microfluidics: Synergy of machine learning and microfluidics in the development of medical diagnostics for chronic and emerging infectious diseases

The COVID-19 pandemic, emerging/re-emerging infections as well as other non-communicable chronic diseases, highlight the necessity of smart microfluidic point-of-care diagnostic (POC) devices and systems in developing nations as risk factors for infections, severe disease manifestations and poor clinical outcomes are highly represented in these countries. These POC devices are also becoming vital as analytical procedures executable outside of conventional laboratory settings are seen as the future of healthcare delivery. Microfluidics have grown into a revolutionary system to miniaturize chemical and biological experimentation, including disease detection and diagnosis utilizing muPads/paper-based microfluidic devices, polymer-based microfluidic devices and 3-dimensional printed microfluidic devices. Through the development of droplet digital PCR, single-cell RNA sequencing, and next-generation sequencing, microfluidics in their analogous forms have been the leading contributor to the technical advancements in medicine. Microfluidics and machine-learning-based algorithms complement each other with the possibility of scientific exploration, induced by the framework's robustness, as preliminary studies have documented significant achievements in biomedicine, such as sorting, microencapsulation, and automated detection. Despite these milestones and potential applications, the complexity of microfluidic system design, fabrication, and operation has prevented widespread adoption. As previous studies focused on microfluidic devices that can handle molecular diagnostic procedures, researchers must integrate these components with other microsystem processes like data acquisition, data processing, power supply, fluid control, and sample pretreatment to overcome the barriers to smart microfluidic commercialization.Copyright © 2023 by Begell House, Inc.

Pancreatic Stone Protein (PSP) as a predictive biomarker of multiple organ failure and clinical outcome

Background: COVID-19 syndrome is associated with high morbidity and mortality in haemodialyzed patients. Pancreatic Stone Protein (PSP) is an early biomarker of sepsis and a prognostic biomarker of disease severity in critically-ill patients and can be rapidly measured at the patient's bedside with a point-of-care-test from a small drop of whole blood. The aim of our pilot was to investigate PSP in patients requiring haemodialysis with SARS-CoV-2 infection, at different severities of COVID-19 disease. Method(s): Between February and July 2021, 23 patients (6 severe COVID-19 with Acute Kidney Injury, 6 moderate COVID-19 haemodialyzed, 2 haemodialyzed without COVID-19 and 3 healthy controls) were recruited at the University Hospital of Foggia for PSP evaluation. Biomarker's measurements were performed within 48 hours after admission or upon arrival for haemodialysis (pre-treatment). PSP was measured at the patient's bedside with "abioSCOPE", a point-of-care test capable of evaluating PSP levels in five minutes from a small drop (50mul) of whole blood or serum. Result(s): The preliminary results of this pilot study showed a trend for PSP to increase along with the severity of disease. In fact, serum PSP levels were significantly higher in Intensive Care Unit subjects than in COVID-19 negative haemodialysis subjects and controls (ANOVA p=0.032). Furthermore, PSP levels were significantly higher in subjects who died (p<0.017). Whether this increase is due to the kidney injury or COVID-19 disease remains unknown, and more research is needed to understand the relationship. Conclusion(s): Several clinical studies published in literature have shown the predictive value of PSP in the early identification of sepsis and severity of the clinical outcome. In our experience we have seen a trend for PSP to increase with disease severity also in COVID-19 patients. These results are preliminary, but PSP was significantly higher in patients who died, in accordance with the literature. This experience also has demonstrated the feasibility of a point of care system to be easily implemented in the unit and adopted by personnel and its design enables fast results and immediate decisions to be taken, especially in urgent situations.

Rapid, sensitive detection of intact SARS-CoV-2 using DNA nets and a smartphone-linked fluorimeter

We report a single-step, room-temperature, 5-10 minute SARS-CoV-2 saliva self-monitoring method that overcomes the limitations of existing approaches through the use of fluorophore-releasing Designer DNA Nanostructures (DDNs) that bind with the multivalent pattern of spike proteins on the exterior intact virions and an inexpensive smartphone-linked, pocket-size fluorimeter, called a "V-Pod” for its resemblance to an Apple AirPod™ headphone case. We characterize the V-Pod fluorimeter performance and the DDN-based assay to demonstrate a clinically relevant detection limit of 104 virus particles/mL for pseudo-typed WT SARS-CoV-2 and 105 virus particles/mL for real pathogenic variants, including Delta, Omicron, and D614g. © 2023 SPIE.

Smart Nanobiosensing for COVID-19 Diagnosis

Repeated public health menace caused by the pathogenic coronaviruses, including the present COVID-19 caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), has had devastating aftereffects, and an intense need for a promising solution has developed. Currently, reverse transcription polymerase chain reaction (RT-PCR) is being extensively utilized for detecting the virus from biological samples. However, it has certain limitations and fails to provide accurate and reliable results. Consequently, simple, portable, and pointof- care testing enabled biosensors have turned up as the most efficient and sustainable diagnostic tool. This review provides a brief introduction about the present global scenario due to the ongoing pandemic and concise information regarding the morphological details of coronaviruses. Thereafter, a summarized data is presented regarding the contemporary biosensing platforms fabricated to specifically identify fatal coronaviruses with particular emphasis towards surface plasmon resonance (SPR)-based biosensor, field-effect transistor (FET)-based biosensor, colorimetric sensors, fluorescence-based sensors, and electrochemical (EC) immunosensors. A comparative analysis of the sensors is also presented along with a few future perspectives that can aid the development of smart and futuristic sensors. This review is expected to provide details to researchers about the ongoing biosensor-related experimentations and encourage them to develop innovative detection devices to manage the current pandemic. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023.

Smartphone-based point-of-care testing of the SARS-CoV-2: A systematic review.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus's worldwide pandemic has highlighted the urgent need for reliable, quick, and affordable diagnostic tests for comprehending and controlling the epidemic by tracking the world population. Given how crucial it is to monitor and manage the pandemic, researchers have recently concentrated on creating quick detection techniques. Although PCR is still the preferred clinical diagnostic test, there is a pressing need for substitutes that are sufficiently rapid and cost-effective to provide a diagnosis at the time of use. The creation of a quick and simple POC equipment is necessary for home testing. Our review's goal is to provide an overview of the many methods utilized to identify SARS-CoV 2 in various samples utilizing portable devices, as well as any potential applications for smartphones in epidemiological research and detection. The point of care (POC) employs a range of microfluidic biosensors based on smartphones, including molecular sensors, immunological biosensors, hybrid biosensors, and imaging biosensors. For example, a number of tools have been created for the diagnosis of COVID-19, based on various theories. Integrated portable devices can be created using loop-mediated isothermal amplification, which combines isothermal amplification methods with colorimetric detection. Electrochemical approaches have been regarded as a potential substitute for optical sensing techniques that utilize fluorescence for detection and as being more beneficial to the Minimizing and simplicity of the tools used for detection, together with techniques that can amplify DNA or RNA under constant temperature conditions, without the need for repeated heating and cooling cycles. Many research have used smartphones for virus detection and data visualization, making these techniques more user-friendly and broadly distributed throughout nations. Overall, our research provides a review of different novel, non-invasive, affordable, and efficient methods for identifying COVID-19 contagious infected people and halting the disease's transmission.

Design and implementation of a digital site-less clinical study of serial rapid antigen testing to identify asymptomatic SARS-CoV-2 infection.

Background: Rapid antigen detection tests (Ag-RDT) for SARS-CoV-2 with emergency use authorization generally include a condition of authorization to evaluate the test's performance in asymptomatic individuals when used serially. We aim to describe a novel study design that was used to generate regulatory-quality data to evaluate the serial use of Ag-RDT in detecting SARS-CoV-2 virus among asymptomatic individuals. Methods: This prospective cohort study used a siteless, digital approach to assess longitudinal performance of Ag-RDT. Individuals over 2 years old from across the USA with no reported COVID-19 symptoms in the 14 days prior to study enrollment were eligible to enroll in this study. Participants throughout the mainland USA were enrolled through a digital platform between October 18, 2021 and February 15, 2022. Participants were asked to test using Ag-RDT and molecular comparators every 48 hours for 15 days. Enrollment demographics, geographic distribution, and SARS-CoV-2 infection rates are reported. Key Results: A total of 7361 participants enrolled in the study, and 492 participants tested positive for SARS-CoV-2, including 154 who were asymptomatic and tested negative to start the study. This exceeded the initial enrollment goals of 60 positive participants. We enrolled participants from 44 US states, and geographic distribution of participants shifted in accordance with the changing COVID-19 prevalence nationwide. Conclusions: The digital site-less approach employed in the "Test Us At Home" study enabled rapid, efficient, and rigorous evaluation of rapid diagnostics for COVID-19 and can be adapted across research disciplines to optimize study enrollment and accessibility.

Recommendations for the integral diagnosis of chronic viral hepatitis in a single analytical extraction. / Recomendaciones para el diagnóstico integral de las hepatitis virales crónicas en una única extracción analítica.

The Spanish Society of Digestive Pathology (SEPD), the Spanish Association for the Study of the Liver (AEEH), the Spanish Society of Infections and Clinical Microbiology (SEIMC) and its Viral Hepatitis Study Group (GEHEP), and with the endorsement of the Alliance for the Elimination of Viral Hepatitis in Spain (AEHVE), have agreed on a document to carry out a comprehensive diagnosis of viral hepatitis (B, C and D), from a single blood sample; that is, a comprehensive diagnosis, in the hospital and/or at the point of care of the patient. We propose an algorithm, so that the positive result in a viral hepatitis serology (B, C and D), as well as human immunodeficiency virus (HIV), would trigger the analysis of the rest of the virus, including the viral load when necessary, in the same blood draw. In addition, we make two additional recommendations. First, the need to rule out a previous hepatitis A virus (VHA) infection, to proceed with its vaccination in cases where IgG-type studies against this virus are negative and the vaccine is indicated. Second, the determination of the HIV serology. Finally, in case of a positive result for any of the viruses analyzed, there must be an automated alerts and initiate epidemiological monitoring.

Impedimetric Sensing: An Emerging Tool for Combating the COVID-19 Pandemic.

The COVID-19 pandemic revealed a pressing need for the development of sensitive and low-cost point-of-care sensors for disease diagnosis. The current standard of care for COVID-19 is quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). This method is sensitive, but takes time, effort, and requires specialized equipment and reagents to be performed correctly. This make it unsuitable for widespread, rapid testing and causes poor individual and policy decision-making. Rapid antigen tests (RATs) are a widely used alternative that provide results quickly but have low sensitivity and are prone to false negatives, particularly in cases with lower viral burden. Electrochemical sensors have shown much promise in filling this technology gap, and impedance spectroscopy specifically has exciting potential in rapid screening of COVID-19. Due to the data-rich nature of impedance measurements performed at different frequencies, this method lends itself to machine-leaning (ML) algorithms for further data processing. This review summarizes the current state of impedance spectroscopy-based point-of-care sensors for the detection of the SARS-CoV-2 virus. This article also suggests future directions to address the technology's current limitations to move forward in this current pandemic and prepare for future outbreaks.

PATHPOD - A loop-mediated isothermal amplification (LAMP)-based point-of-care system for rapid clinical detection of SARS-CoV-2 in hospitals in Denmark.

Sensitive and rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been a vital goal in the ongoing COVID-19 pandemic. We present in this comprehensive work, for the first time, detailed fabrication and clinical validation of a point of care (PoC) device for rapid, onsite detection of SARS-CoV-2 using a real-time reverse-transcription loop-mediated isothermal amplification (RT-LAMP) reaction on a polymer cartridge. The PoC system, namely PATHPOD, consisting of a standalone device (weight less than 1.2 kg) and a cartridge, can perform the detection of 10 different samples and two controls in less than 50 min, which is much more rapid than the golden standard real-time reverse-transcription Polymerase Chain Reaction (RT-PCR), typically taking 16-48 h. The novel total internal reflection (TIR) scheme and the reactions inside the cartridge in the PoC device allow monitoring of the diagnostic results in real-time and onsite. The analytical sensitivity and specificity of the PoC test are comparable with the current RT-PCR, with a limit of detection (LOD) down to 30-50 viral genome copies. The robustness of the PATHPOD PoC system has been confirmed by analyzing 398 clinical samples initially examined in two hospitals in Denmark. The clinical sensitivity and specificity of these tests are discussed.

Performances of Dried Blood Spots and Point-of-Care Devices to Identify Virological Failure in HIV-Infected Patients: A Systematic Review and Meta-Analysis.

To broaden access to HIV viral load monitoring (VLM), the use of blood samples from dried blood spots (DBS) or point-of-care (POC) devices, could be of great help in settings where plasma is not easily accessible. The variety of assays available makes the choice complex. This systematic review and meta-analysis aims to estimate the sensitivity and specificity of DBS and POC devices to identify patients in virological failure using World Health Organization (WHO) recommendations (viral load ≥1000 copies/mL), compared with plasma, for the assays currently available. Four databases were searched for articles, and two reviewers independently identified articles reporting sensitivity and specificity of DBS and/or POC to identify patients in virological failure. We excluded articles that used other thresholds as well as articles with a total number of participants below 50 to avoid reporting bias. Heterogeneity and factors associated with assays' performances were assessed by I2 statistics and metaregression. The protocol of this review follows the PRISMA guidelines. Out of 941 articles, 47 were included: 32 DBS evaluations and 16 POC evaluations. Overall, when using DBS, the Abbott RT HIV-1, Roche CAP-CTM, NucliSENS BioMerieux and Aptima assays presented sensitivity and specificity exceeding 85%, but reported results were highly heterogeneous. Factors associated with better performances were high volume of blood and the use of the same assay for DBS and plasma VLM. Regarding the POC devices, SAMBA I, SAMBA II, and GeneXpert devices presented high sensitivity and specificity exceeding 90%, with less heterogeneity. DBS is suitable VLM, but performances can vary greatly depending on the protocols, and should be performed in trained centers. POC is suitable for VLM with less risk of heterogeneity but is more intensive in costs and logistics.