REASSURED diagnostics to inform disease control strategies, strengthen health systems and improve patient outcomes

Clinical utility of a glycosylated fibronectin test (LumellaTM) for assessment of impending preeclampsia

OBJECTIVE

Preeclampsia is a major pregnancy complication that results in significant maternal and infant mortality and morbidity, yet difficulties remain in the diagnosis of preeclampsia based on clinical parameters alone. The objective was to assess the performance of a hand-held point-of-care (POC) immunoassay in a clinical environment for glycosylated fibronectin (GlyFn) for the prediction of preeclampsia within 4 weeks of sampling.

METHODS

Multinational European prospective observational pilot study of predominantly high-risk patients in the second half of pregnancy to assess a point-of-care immunoassay for GlyFn in predicting preeclampsia within 4 weeks of sampling. GlyFn was measured using a second generation hand held POC immunoassay. Results were considered normal for GlyFn concentrations of < 350 µg/mL, positive for GlyFn concentrations of 351-600 µg/mL, and high-positive for GlyFn concentrations > 600 µg/mL.

RESULTS

Preeclampsia developed in 16 (19%) of 84 subjects and was associated with a shorter gestational age at delivery 35.3 weeks vs. 37.3 weeks for non-preeclamptics, n = 82; p = 0.001), a higher risk of fetal growth restriction (FGR; 31.2% vs. 10.3% for non-preeclamptics, p = 0.046), and an increased risk of preterm birth < 37 weeks gestation (83.3% vs. 33.3% for non-preeclamptics, (n = 78; p = 0.003). GlyFn positive or high positive was seen in 13/16 (81%) and in 35/68 (51.5%), yielding a sensitivity of 81%, a specificity of 49%, a positive predictive value of 27%, and a negative predictive value of 92%. GlyFn positive or high positive was also associated with preterm birth < 37 weeks in singleton pregnancy non-preeclamptic patients. Preterm birth occurred in 4.8% of those with normal GlyFn, in 26.7% with positive GlyFn, and in 50% of those with high GlyFn in singleton gestations without preeclampsia (p = 0.008).

CONCLUSION

The ability to use this test in a POC format provides a method for practitioners to quickly determine risk for preeclampsia in their pregnant patients and offers an affordable alternative, as a single analyte to other diagnostic or screening tests that require laboratory-based testing or ultrasound equipment. Independent of preeclampsia, an elevated GlyFn was also correlated with preterm delivery and requires further study.

Portable electrophoretic lateral flow biosensing for ultra-sensitive human lactate dehydrogenase detection in serum samples

Lateral flow immunoassays are globally recognized for their simplicity, cost-effectiveness, and rapid qualitative and semiquantitative analyses, making them indispensable as point-of-care screening tools. However, their limited sensitivity restricts their application in clinical settings, requiring the detection of ultralow analyte concentrations in complex sample matrices. To address these challenges, we present a portable biosensing platform integrating battery-powered electrokinetic-driven microfluidics to enhance sensitivity while preserving point-of-care functionality. Our lightweight (151 g), 3D-printed electrophoretic device (€82) supports the simultaneous analysis of three samples and operates with an ultra-low power consumption of 225 mAh-1, enabling 44 h of operation on a single charge. By optimizing key parameters such as Joule heating, buffer evaporation, and electroosmotic flow, the device enables iterative incubation and washing steps directly on the nitrocellulose strip, capabilities unattainable with conventional capillarity-driven LFIAs. This advanced biosensing platform achieves a detection limit of 70 pg mL-1 for human lactate dehydrogenase (h-LDH), a key cancer biomarker, using gold nanoparticles as signal transducers. This result means a 367-fold improvement in sensitivity. Offering rapid, cost-effective, and ultra-sensitive biomarker quantification, this approach holds significant promise for transforming precision medicine, particularly in monitoring LDH-related cancer therapies.

Ultrafast cell-free DNA extraction from body fluids using UiO-66-NH2 hydrogel packed syringe

Liquid biopsy represents a noninvasive or minimally invasive diagnostic approach relevant for both the organ-specific changes and systemic health conditions, whereas cell-free DNA (cfDNA) extraction from body liquids has attracted much attention in liquid biopsy, especially. Nowadays, metal-organic frameworks (MOF) such as UiO-66-NH2 has been demonstrated efficient extraction property for DNA molecular, whereas the disadvantages of MOF for solid-phase extraction (SPE) still remain. Herein, one macro-pored MOF hydrogel formation strategy was constructed in this study to achieve superb extraction performance of cfDNAs from body fluids. The MOF crystals were embedded into sodium alginate, which was foamed using laurinol, pre-crosslinked through polyethyleneimine (PEI), and cured by zirconium ion at last. Validation of cfDNA extraction from human gingival crevicular fluid and plasma indicated that hydrogel beads allowed unimpeded flow of body fluids while enabling ultrafast extraction and elution of cfDNAs. Consequently, MOF hydrogel beads, when packed atop the syringe pintle as SPE column, achieved an efficient cfDNA extraction only within 6 min. Our construction strategy of extracting syringe provides an instrument-free purification modality of nucleic acid, which would tremendously simplify and quicken cfDNA extraction procedures for operators.

Development of a single-tube RPA/CRISPR-cas12a detection platform for monkeypox virus

Monkeypox is a zoonotic disease caused by the monkeypox virus (MPXV), with outbreaks primarily occurring in West and Central Africa. The recent global MPXV outbreak underscores the urgent need for effective detection methods. Currently, qPCR is considered the gold standard for MPXV detection; however, it requires specialized personnel and costly equipment. This study introduces a CRISPR-Cas12a-based detection system targeting the MPXV A27L gene, achieving a detection limit as low as 10 aM. This system exhibits high specificity, with no cross-reactivity with other orthopoxviruses, and delivers results in under 40 min. To support point-of-care testing (POCT), we developed a lateral flow assay (LFA) strip for easy result visualization. The detection system was validated using six different clinical sample types, revealing that herpes fluid and saliva are the most suitable sources. The findings of this study align with qPCR results. Additionally, we lyophilized the RPA and CRISPR reagents to improve transport, storage, and field deployment. In conclusion, this study presents a reliable molecular diagnostic approach for early MPXV detection and point-of-care testing, contributing to epidemic prevention and control.

Recent advances in dynamic single-molecule analysis platforms for diagnostics: Advantages over bulk assays and miniaturization approaches

Single-molecule science is a unique technique for unraveling molecular biophysical processes. Sensitivity to single molecules provides the capacity for the early diagnosis of low biomarker amounts. Furthermore, the miniaturization of instruments for portable diagnostic tools toward point-of-care testing (POCT) is a crucial development in this field. Herein, we discuss recent developments in single-molecule sensing platforms and their advantages for diagnostics over bulk measurements including molecular size measurements, interaction dynamics, and fast biomarker sensing and sequencing at low concentrations. We highlight the capabilities of dynamic optical and electrical sensing platforms for single-biomolecule and single-vesicle monitoring associated with neurodegenerative disorders, viral diseases, cancers, and more. Current approaches to instrument miniaturization have brought technology closer to portable diagnostics settings via smartphone-based devices, multifunctional portable microscopes, handheld electrical circuit devices, and remote single-molecule assays. Finally, we provide an overview of the clinical applications of single-molecule sensors in POCT assays. Altogether, single-molecule analyses platforms exhibit significant potential for the development of novel portable healthcare devices.

Amplifying visible signals in lateral flow assays using integrated nanoelectrokinetics

In this study, we developed a tangential nanoelectrokinetic force-enhanced lateral flow assay by integrating a Nafion-cellulose nanofibrils hybrid gel to improve conventional lateral flow assay performance without external instrumentation. Our assay was designed by embedding the Nafion-cellulose nanofibrils gel beneath the test line, generating a tangential nanoelectrokinetic force that enhances the migration and accumulation of antigen-AuNP probe complexes within the visible depth of the nitrocellulose surface. The proposed assay exhibited a 32.5-fold improvement in the limit of detection for COVID-19 nucleocapsid protein, achieving a 0.24 ng/mL. Clinical trials demonstrated 100% sensitivity and 100% specificity, far surpassing the performance of conventional lateral flow assays, which typically achieve 66.7 % sensitivity and 100 % specificity. Our assay also demonstrated high selectivity, with no cross-reactivity against other respiratory pathogens such as respiratory syncytial virus A, respiratory syncytial virus B, OC43 (COVID), influenza A, and influenza B, making it a robust and cost-effective solution for point-of-care diagnostics, particularly in resource-limited settings.

Broad-spectrum antibody against thiazides and degraded salamide and immunoassay establishment for simultaneous detection

The illegal additive thiazides and degraded salamide in food supplements poses significant health risks and regulatory challenges. However, the structural differences between thiazides and salamide complicate the hapten design for immunoassay detection. In this study, we first outlined the common skeleton of thiazides and their shared epitopes with salamide through molecular overlap and atomic charge distribution analysis. Several haptens were rationally designed based on the private epitope of salamide and the shared epitopes with thiazides, assisted by computer-aided chemical analysis. Subsequently, the resultant monoclonal antibody exhibited broad specificity for thiazides (IC50 value = 21.43-405.40 ng/mL) and salamide (IC50 value = 0.76 ng/mL). The immunoassay affinities of 5 of these thiazides are reported for the first time. Further elucidation of the intrinsic recognition mechanism was achieved through homology modeling and molecular docking, clarifying the antibody's diverse recognition spectrum. Finally, we established a rapid, reliable colloidal gold-based immunochromatography strip for simultaneous detecting total thiazides and degraded salamide in food supplements and surface water sample for the first time. The cut-off value was as low as 7.5 ng/mL, which was 32 times more sensitive than that of established immunoassays for thiazides.

Challenges and opportunities for AMR research in the ASEAN following the One Health approach

Background

Antimicrobial resistance (AMR) has emerged as a significant global challenge and Southeast Asia with rapid economic and population growth faces substantial challenge in dealing with emerging infectious diseases and antimicrobial resistance. Here we present the recommendations of a workshop that explored the challenges and opportunities for One Health approach towards AMR research in three countries of AEAN, namely, Cambodia, Laos, and Vietnam.

Methods

A workshop was organised in Hanoi, Vietnam in August 2023, involving participants involved in AMR research across varied sectors from three participating countries to prioritise the strategies that can be implemented in the region to fructify the One Health approach to tackle AMR. A modified Delphi approach was used to prioritise the top 10 Global Priority Research Questions for the region as developed by the Quadripartite (FAO, WHO, WOAH and UNEP). An iterative process was adopted to map priorities according to their impact and feasibility of application.

Results

Collaborative initiatives, such as a common platform for listing the research goals, a web-based surveillance mechanism, and an enhanced AMR awareness curricula were identified as the steps forward. A consensus statement highlighting the critical needs for improved technical and infrastructure capacity, collaboration between sectors, increased funding, and systematic data analysis was drafted.

Discussion

The participating countries have National Action Plans guided by the World Health Organization's Global Action Plan on AMR, but limited collaboration between human health and other sectors has impeded the benefits that One Health approach may achieve in the region. The recommendations include the need for improved technical and infrastructure capacity, and data collection across One Health sectors, besides increasing awareness at multiple levels.

Conclusion

A collaborative and coordinated effort to apply One Health initiatives for tackling AMR in the ASEAN region is imperative. The workshop formulated a roadmap for future direction by identifying priorities aimed at enhancing collaboration, addressing infrastructure gaps, and contributing to an effective intervention in the fight against AMR in the region.

A Colorimetric Biosensor Integrating Rotifer-Mimicking Magnetic Separation with RAA/CRISPR-Cas12a for Rapid and Sensitive Detection of Salmonella

Efficient detection of foodborne bacteria is crucial for ensuring food safety, yet current methods often fall short in balancing speed, accuracy, sensitivity, and cost. This study presents an integrated biosensing platform for the rapid and sensitive detection of Salmonella in large-volume food samples. The platform incorporates a Rotifer-Mimicking Magnetic Separator (RMMS) that enhances the sample pretreatment by effectively mixing and isolating the bacteria from the sample. Coupled with this, the colorimetric biosensor utilizes a streamlined one-pot system that combines Recombinase Aided Amplification (RAA), betaine, and CRISPR-Cas12a to enable efficient pathogen detection. Initially, phenylboronic acid-modified magnetic beads (PBA-MBs) capture Salmonella, forming bacteria-PBA-MB complexes, which are then isolated using the RMMS. Target DNA amplicons activate ribonucleoprotein complexes, and Au@PtNPs-MBs with linker single DNAs are cleaved to release Au@PtNPs. The Au@PtNPs catalyze the H2O2-3,3',5,5'-tetramethylbenzidine, producing a visible blue color that indicates Salmonella concentration. This biosensor successfully detects Salmonella in 40 mL spiked milk samples within 75 min, achieving a detection limit of 89 CFU/mL. This work offers a simple, sensitive, low-cost detection method with potential applications in on-site testing, significantly enhancing food safety monitoring.

Paper as a Sustainable Material for Smart Electrochemical (Bio)sensors with Unprecedented Features: A Perspective

This perspective has the overriding goal of reporting the tipping points in the roadmap of electrochemical paper-based analytical devices by harnessing the multiple paper characteristics such as cost-effectiveness, widespread accessibility, mechanical strength, porosity, and capability to be easily cut, folded, modified, and assembled. The use of paper in electrochemical devices not only provides additional features to the electrochemical devices such as the environmentally friendless, ease multiplexed analysis, and three tridimensional structures by folding and unfolding operations but has broken down barriers for delivering measurement without (i) addition of reagents, (ii) sample treatment for liquid, aerosol, and solid samples, and (iii) any additional pump for microfluidics. I lay out the advantages of using paper for the design of multifarious electrochemical devices, underlying the next steps in the paper-based electrochemical device roadmap.

Technical validation of a multiplex real-time PCR for combined detection of Rift Valley fever, chikungunya, Zika and dengue viruses

Several arthropod-borne (arbo)-viruses have overlapping symptoms, insect vectors and geographical occurrence. With little known about the importance of arboviruses as cause of acute undifferentiated fever (AUF) in East and Central Africa (ECA), there is a clear need for a multiplex-PCR allowing for multi-pathogen surveillance. A multiplex real-time RT-PCR (RDCZ-multiplex) was developed and validated for the simultaneous detection of Rift Valley fever virus (RVFV), dengue virus 1-4 (DENV), chikungunya virus (CHIKV) and Zika virus (ZIKV). Phocine distemper virus (PDV) was added to the PCR as sample extraction control. Validation was conducted following the MIQE-guidelines using a panel of retrospective clinical samples and Quality Control for Molecular Diagnostics (QCMD, https://www.qcmd.org/en/) samples with the simplex-PCR as reference. These included samples from RVFV in animals (n=19), DENV (n=15), CHIKV (n=11), ZIKV (n=2) and YFV (n=1, QCMD), and 14 negative endemic controls. Extractions and PCRs were done with commercially available kits. Some loss of sensitivity was observed at low target concentrations for RVFV, DENV1 and DENV4, when comparing the standard curves of simplex-PCRs with the multiplex-PCR. The limit of detection of the multiplex-PCR was 2,064 copies/mL for CHIKV, 3,587 copies/mL for DENV1, 30,249 copies/mL for ZIKV and 73 PFU/mL for RVFV. Specificity of the multiplex-PCRs was 100%. For 12 out of 48 positive samples with high Cq values, RVFV (n=7), CHIKV (n=2), DENV1 (n=2), YFV (n=1), the multiplex-PCRs were negative. Although PCR sensitivity of the RDCZ-multiplex is slightly lower with low target concentrations, it offers a useful tool for molecular surveillance and clinical diagnosis for arboviruses for the ECA-region.

All-Inclusive Sensing Tablet with Integrated Passive Mixer for Ultraviscous Solutions

Developing low-cost and easy-to-use point-of-care devices is necessary for timely disease diagnosis and health monitoring. Here, we introduce all-inclusive, tablet-based chemo/biosensors with rapid automixing features, capable of mixing in highly viscous solutions with viscosities up to 1700 mPa·s. These tablets are created using a simple powder compression method and contain all necessary reagents to perform assays in a "drop-and-detect" manner, without the need for vigorous shaking or vortex mixing. As proof of concept, we demonstrated the applicability of our Speedy tablets for detecting nitrite in human saliva, a challenging medium due to its viscosity. The strong mixing capability of the proposed tablets ensured consistent and reliable results across range of viscosities, from low to high, while delivering an excellent detection range of 0.03-1.50 mg/dL, covering nitrite levels in human saliva. Additionally, we developed a straightforward method to encapsulate enzymes in trehalose, making them bulkier and more stable using only a mist sprayer, nonstick tray, and spatula, eliminating the need for expensive equipment. This approach allowed us to incorporate small amounts of enzymes into tablet formulations and fabricate the first automixing tablet biosensor. These biosensors were used for the bienzymatic detection of glucose in real human urine within the biologically relevant range of 0.3-2.5 mM, indicating the compatibility of automixing tablets with bioreagents. Each tablet costs less than $0.30 to produce and remains stable for at least one month at room temperature. The affordability and convenience of our tablets make them a valuable addition to the array of diagnostic tools.

Up-to-date nucleic acid assays for diagnosing respiratory infection

Nucleic acid assays have been widely used as rapid tests for diagnosing respiratory infections during and after the coronavirus disease 2019 (COVID-19) pandemic. An ideal point-of-care diagnostic must be affordable, sensitive, specific, user-friendly, rapid/robust, equipment-free and deliverable (ASSURED), and in addition to improvements to conventional methods based on polymerase chain reaction (PCR), point-of-care testing aiming for "REASSURED" are emerging through integration with microfluidic technology. Compared to conventional immunoassays, nucleic acid assays, especially rapid nucleic acid assays as point-of-care testing, contribute to improvements in various clinical outcomes, such as diagnostic yield, turnaround time, length of hospital stay, disease treatment, and infection control management. Rapid and diverse development of new nucleic acid-based molecular diagnostic technologies, such as those based on the CRISPR/Cas system or biosensor nucleic acid assays, is expected to become increasingly diverse in the future as point-of-care testing. In addition, laboratory-based DNA sequencing technology has been used to perform microbiome analyses over a wide area and is expected to shed light on the pathological mechanisms of various respiratory infectious diseases. One example of the benefits of nucleic acid amplification analysis methods is their ability to reveal the true nature of the bacterial flora in pneumonia lesions. This has been demonstrated based on the results of 16S ribosomal RNA gene sequencing analyses using bronchoalveolar lavage fluid directly obtained from pneumonia lesions in patients with pneumonia.

Rapid diagnosis of urinary tract infection with miniaturised point-of-care cultivation on a dipstick

PURPOSE

Urinary Tract InfectionAQ1 (UTI) affects over 400 million people annually and globally and is a major reason for empiric antibiotic prescription by general practitioners (GPs).

BACKGROUND

A problem related to microbiological UTI diagnosis is the current lack of point of care (POC) diagnostics. In addition, remote settings, including low and middle income countries (LMIC), are hard to service. Compliance with requirements posed by the In Vitro Diagnostic Regulation (IVDR) and adherence to guidelines as defined by professional user groups are mandatory to pursue. In addition, the World Health Organisation (WHO) promotes optimization of antimicrobial use and more adequate microbiological diagnostics to cure UTI and combat antimicrobial resistance (AMR).

METHODS

Miniaturised chromogenic bacterial cultivation including rapid antimicrobial susceptibility testing (RAST) at the POC can be successfully used for the diagnosis of UTI. Using small and cost-effective dipsticks containing chromogenic cultivation media, UTI-causing bacteria can be detected, quantified and identified with good sensitivity and specificity.

CONCLUSION

Access to such trustworthy, easy-to-use and cost-efficient diagnostic tools at the POC would offer more timely results for optimised antibiotic treatment. This will improve UTI therapy and prevent AMR.

The development of a multiplex recombinase polymerase amplification reaction to detect the most common causative agents of eumycetoma

PURPOSE

Mycetoma is a neglected tropical disease that affects the subcutaneous tissue. The disease can be caused by over 90 different pathogens, including both bacteria (actinomycetoma) and fungi (eumycetoma). While diagnostic tools for eumycetoma causative agents are available, these are generally not well suited for use in endemic regions. This study aims to develop an isothermal based multiplex recombinase polymerase amplification reaction (RPA), that can be integrated in the diagnostic workflow of endemic regions.

METHODS

The RPA was designed targeting the Internal Transcribed Spacer (ITS) region to detect the presence of fungal DNA, and to differentiate between Madurella mycetomatis and Falciformispora senegalensis. The performance of the RPA was evaluated using 71 fungal isolates and five actinomycetes reference isolates. Furthermore, the limit of detection (LOD) was determined for the different probes in singleplex and multiplex.

RESULTS

The ITS probe was positive for all 71 fungal isolates with a mean detection time of 13.1 min. The M. mycetomatis and F. senegalensis probes were only positive for their respective targets, with a mean detection time of 9.3 and 7.6 min, respectively. No cross-reactivity was detected, and a limit of detection of 0.01 ng of fungal DNA was found. The costs of the RPA ranged from €1.56 to €10.03, depending on the workflow.

CONCLUSION

We developed a field-friendly multiplex RPA, that successfully detects fungal DNA and discriminates between M. mycetomatis and F. senegalensis. This tool holds promise for enhancing diagnostic capabilities in eumycetoma endemic regions, paving the way for improved patient management and treatment outcomes.

Development and optimization of an antibody-free nucleic acid lateral flow assay (AF-NALFA) as part of a molecular toolkit for visual readout of amplified Listeria monocytogenes DNA

Listeria monocytogenes is a Gram-positive foodborne pathogen responsible for listeriosis, a severe disease with high mortality in immunocompromised individuals. Rapid and accurate detection in food samples is essential for food safety. In this study, we developed and optimized an Antibody-Free Nucleic Acid Lateral Flow Assay (AF-NALFA) as part of a molecular detection toolkit for the visual readout of amplified L. monocytogenes hlyA gene, in combination with ultra-fast asymmetric PCR (aPCR) and oligonucleotide probe hybridization. Three critical parameters were optimized: oligonucleotide probe concentration on test and control lines, gold nanoparticle-probe conjugation ratio, and running buffer composition. In pure bacterial cultures, the limit of detection (LOD) of AF-NALFA was 12.62 copies for L. monocytogenes ATCC 7644, 8.68 copies for ATCC 19117, and 4.83 copies for ATCC 13932. These values were quantitatively assessed using qPCR, confirming the assay's consistency in detecting low DNA copy numbers. The prototype demonstrated 100% specificity against 13 other bacterial species. Furthermore, it was successfully tested in artificially contaminated UHT milk after 1 year of storage at room temperature, detecting L. monocytogenes at 1-30 CFU/mL without DNA purification or selective enrichment. The AF-NALFA enabled visual detection of target ssDNA hybridization within 20 min, offering a rapid, cost-effective alternative to DNA detection methods requiring expensive equipment, specialized expertise, and time-consuming procedures. These findings highlight AF-NALFA's potential as a complementary tool for L. monocytogenes surveillance, providing a practical solution for rapid screening in food safety laboratories and epidemiological monitoring.

A streamlined POCT solution for rapid infectious disease detection

Point-of-care testing (POCT) plays a crucial role in infectious disease screening due to its rapid detection and portability. However, current POCT systems face challenges such as lengthy sample preparation time, complex nucleic acid extraction, and limited real-time data transmission, extending patient waiting time. This study presents iPonatic, an integrated POCT system with a quantitative dropper for efficient sample addition, a low-cost cartridge utilizing one-step rapid nucleic acid release technology, and real-time data synchronization via a cloud platform. Patients can receive test reports within 30 min. The system was validated for both respiratory and sexually transmitted pathogens, showing consistent [Formula: see text] values with standard quantitative PCR. Clinical validation on 1159 samples demonstrated an AUC above 0.98 for all targets, with sensitivity exceeding 95% and specificity reaching 100%. iPonatic is ideal for primary healthcare, epidemic response, and resource-limited settings. It offers an efficient solution to enhance diagnostics and reduce patient waiting time, supporting timely responses to public health needs.

Advances in the recombinase polymerase amplification platform for urogenital schistosomiasis diagnosis (ShDraI-RPA) towards implementation at the point-of-care

Accurate diagnosis of schistosomiasis is crucial to achieve disease elimination as a public health problem. Rapid and highly sensitive diagnostic tools that can be used in decentralized environments and/or at the point-of-care are needed. This work optimises and simplifies an existing isothermal molecular diagnostic platform (recombinase polymerase amplification, RPA) for urogenital schistosomiasis, the ShDraI-RPA, with a focus on delivering a more accurate diagnosis in endemic settings. The standard ShDraI-RPA oligonucleotides were modified, incorporating a phosphorothioate backbone into the reverse primer and inverting the probe fluorophore and quencher, to prevent false positive results due to secondary structure formation. The sensitivity and specificity of the modified assay were evaluated on a donor urine spiked with one S. haematobium egg and an array of other schistosomes and human urinary tract pathogens. The stability of RPA reagents was assessed by storing them at ambient temperature (± 27 °C) in a dark environment for up to 90 days. Sample preparations were explored to develop a simple, rapid and low resource methodology that would complement the ShDraI-RPA platform when used in remote settings. The modified ShDraI-RPA assay was robust, sensitive and specific to S. haematobium group species, detecting down to 10 fg of gDNA and ten synthetic Dra I copies. DNA amplification was achieved at 42 °C within 20 min and results could easily be visualized using a portable fluorometer or under blue light. RPA reagents remained stable when stored in the absence of light at ± 27 °C for up to 30 days. A two-step DNA extraction method proved optimal for extracting DNA from single S. haematobium eggs in spiked urine. The optimized ShDraI-RPA platform shows improved specificity and sensitivity and has now reached several of the target product profile requirements set out by the WHO for the ideal diagnostic test for schistosomiasis.

Body fluid diagnostics using activatable optical probes

In vitro diagnostics often detects biomarkers in body fluids (such as blood, urine, sputum, and cerebrospinal fluids) to identify life-threatening diseases at an early stage, monitor overall health, or provide information to help cure, treat, or prevent diseases. Most clinically used optical in vitro diagnostic tests utilize dye-labeled biomolecules for biomarker recognition and signal readout, which typically involve complex steps and long processing times. Activatable optical probes (AOPs), which spontaneously activate their optical signals only in the presence of disease biomarkers, offer higher signal-to-background ratios and improved detection specificity. They also have the potential to simplify detection procedures by eliminating multiple washing steps. In this review, we summarize recent advances in the use of AOPs for pre-clinical and clinical body fluid diagnostics across various diseases, including cancer, nephro-urological disorders, infectious diseases, and digestive diseases. We begin by discussing the molecular design strategies of AOPs to achieve different optical signal readouts and biomarker specificity. We then highlight their diagnostic applications in various disease models and body fluids. Finally, we address the challenges and future perspectives of AOPs in enhancing body fluid diagnostics and advancing precision medicine.

Proficiency and associated factors of laboratory professionals in sputum smear microscopy at selected peripheral public and private diagnostic laboratories in Ethiopia: cross-sectional study

BACKGROUND

In countries with a high prevalence of TB, such as Ethiopia, direct sputum smear microscopy remains the most cost-effective tool for diagnosing patients with infectious tuberculosis and monitoring their progress on treatment. However, poor-quality sputum microscopy services may lead to the failure to detect persons with active tuberculosis and may cause unnecessary anti-TB treatment for non-TB cases. Proficiency level is the percentage agreement between participants'readings and the reference panel results. The aim of this study was to assess proficiency and associated factors of laboratory professionals in sputum smear microscopy for acid-fast bacilli at selected peripheral public and private diagnostic laboratories in East Gojjam Zone, Northwest Ethiopia, in 2023.

METHOD

An institutional-based cross-sectional study design was conducted from March 2023 to June 2023 at selected peripheral public diagnostic laboratories in East Gojjam Zone. 65 laboratory professionals were selected randomly from 41 peripheral public diagnostic laboratories in the study area. A validated questionnaire and 10 panel slides were used as data collection tools. The panel consisted of 5 pre-stained and 5 unstained slides. Data were entered and analyzed using the Statistical Package for Social Sciences software (SPSS version 20). P values less than 0.05 were considered statistically significant when looking for associations between dependent and independent variables.

RESULT

The overall proficiency level of laboratory professionals in tuberculosis smear microscopy was 81.92% with 95% CI [78.46-85.38]. Previous TB smear microscopy training, work experience, and institution of education had a significant association with the overall performance of laboratory professionals in TB smear microscopy.

CONCLUSION

The overall TB smear microscopy performance level of laboratory professionals at peripheral diagnostic laboratories in Ethiopia, was satisfactory, indicating a good level of competence. However, notable technical errors related to smear reading and reporting were observed. Thus, higher education institutions, especially private institutions, and the Zonal Health Department, should implement educational and training interventions to address the identified gaps and ultimately contribute to the national TB control program.

Rapid tuberculosis diagnosis from respiratory or blood samples by a low cost, portable lab-in-tube assay

Rapid portable assays are needed to improve diagnosis, treatment, and reduce transmission of tuberculosis (TB), but current tests are not suitable for patients in resource-limited settings with high TB burden. Here we report a low complexity, lab-in-tube system that is read by an integrated handheld device that detects Mycobacterium tuberculosis (Mtb) DNA in blood and respiratory samples from a variety of clinical settings. This microprocessor-controlled device uses an LCD user interface to control assay performance, automate assay analysis, and provide results in a simple readout. This point-of-care single-tube assay uses a DNA enrichment membrane and a low-cost cellulose disc containing lyophilized recombinase polymerase amplification and CRISPR-Cas12a reagents to attain single-nucleotide specificity and high sensitivity within 1 hour of sample application, without a conventional DNA isolation procedure. Assay results obtained with serum cell-free DNA isolated from a cohort of children aged 1 to 16 years detected pulmonary and extrapulmonary TB with high sensitivity versus culture and GeneXpert MTB/RIF results (81% versus 55% and 68%) and good specificity (94%), meeting the World Health Organization target product profile criteria for new nonsputum TB diagnostics. Changes in assay results for serum isolated during treatment were also highly predictive of clinical response. Results obtained with noninvasive sputum and saliva specimens from adults with bacteriologically confirmed pulmonary TB were also comparable to those reported for reference methods. This rapid and inexpensive lab-in-tube assay approach thus represents one means to address the need for point-of-care TB diagnostics useable in low-resource settings.

A New Chemiluminescence-Based Rapid Diagnostic Testing Platform with Sequential Dual-Flow Strips for Cardiac Troponin I (cTnI)

Although the most commonly used method for enhancing a limit of detection (LoD) in immunoassay is adopting chemiluminescence (CL), the liquid form of CL substrates has hindered its use for rapid diagnostic testing (RDT). In order to use the CL-based immunoassay in RDT with minimal user intervention, the liquid CL substrate should be converted to a dry form. In addition, a new RDT platform that is able to perform two sequential flows needs to be developed for the sequential flow control of the CL substrate. In this work, we have successfully developed a new dry form of CL substrate on the strip using a lyophilization process, as well as new lateral flow strips using an additional membrane pad for a time delay to achieve the desired sequential dual flows. Thus, on the dual-flow RDT strips, first the detection antibody conjugated with an enzyme flows over the test and control lines, and then the reconstituted CL substrate flows later. A hydrophilic PVDF membrane was selected as a pad material for the time delay to achieve the sequential dual flows through two flow paths, and flow introduction timing was functionally controlled to secure the time delay of approximately 5 minutes desired between the two flows. A CL-based cardiac troponin I (cTnI) assay was successfully performed on the new dual-flow RDT platform with a sample volume of 120 μL, achieving a LoD of 100 pg/mL. The achieved LoD is better than those possible with most of the currently available RDTs on the market. The new CL-based RDT platform with the capability of dual flows developed in this work can be used for numerous other immunodiagnostic platforms which need further high-sensitivity detection, envisaging a new RDT platform for point-of-care testing with further quantitative analysis.

Hydrogel-Based In Situ DNA Extension Assay for Multiplexed and Rapid Detection of MicroRNA

MicroRNAs (miRNAs) are important biomarkers for liquid biopsy, with extensive applicability to diverse diseases. Among diverse miRNA sensing platforms, graphically encoded hydrogel-based miRNA detection technology is a highly promising diagnostic tool, in terms of sensitivity, specificity, and multiplexing capability. However, the conventional hydrogel-based miRNA detection process suffers from a long assay time (more than 3 h) and redundant assay steps, limiting the practical applicability to actual clinical fields. In this study, we develop a hydrogel-based in situ DNA extension assay for rapid, simple, and multiplexed miRNA detection. Unlike typical hydrogel-based assays, the target hybridization and biotinylation for fluorophore labeling are integrated into a single step via target miRNA-primed DNA extension in hydrogel microparticles. Therefore, multiple microRNA targets can be quantitatively detected within 45 min by two assay steps composed of (1) target capture/biotinylation and (2) fluorophore labeling via streptavidin-biotin interaction. We validate robust sensitivities (down to the low picomolar level) and specificities (single-nucleotide level) by conducting singleplex assays for breast cancer-related miRNA markers (miR-16, miR-92a, and let-7a). Furthermore, multiplexed detection of these miRNA markers is conducted to validate robust multiplexing capacity with negligible nonspecific signal expression. Finally, multiple types of miRNAs in the lysate of breast cancer cells (MCF-7) are successfully detected using the developed assay. We expect the developed hydrogel-based assay can contribute to biomedical and omic fields, enabling high-throughput profiling of multiple miRNAs.

Evaluating the performance of common reference laboratory tests for acute dengue diagnosis: a systematic review and meta-analysis of RT-PCR, NS1 ELISA, and IgM ELISA

BACKGROUND

Dengue fever is listed among the top ten global health threats by WHO. Prompt identification of dengue virus can guide clinical management and outbreak response, yet laboratory diagnosis is complex, costly, and lacks consensus on performance evaluation. This systematic review aims to provide reliable diagnostic accuracy estimates in order to inform global guidance and evaluate novel rapid diagnostic tests.

METHODS

In this systematic review and meta-analysis, we searched nine literature databases on Feb 16, 2021, for reports on five common reference tests for dengue infection: NS1 ELISA, IgM ELISA, IgG ELISA, RT-PCR, and viral neutralisation test. Articles were included if they reported primary data from more than five participants to complete 2×2 tables comparing one of these tests (on human serum) with any comparator. Diagnostic accuracy was estimated using Bayesian random-effect meta-analysis, which does not require a gold-standard comparator. Risk of bias was assessed using QUADAS-2. This review is registered with PROSPERO (CRD42022341552).

FINDINGS

Data were extracted from 161 articles, allowing analysis of multiple timeframes for three tests of interest. Pooled sensitivities of RT-PCR (0-4 days after symptom onset), NS1 ELISA (0-4 days), and IgM ELISA (1-7 days) were 95% (95% credible interval 77-99), 90% (68-98), and 71% (57-84), respectively. The corresponding pooled estimates of specificity were 89% (60-98), 93% (71-99), and 91% (82-95). A subanalysis of only studies at low risk of bias demonstrated similar estimates.

INTERPRETATION

IgM ELISA shows poor diagnostic accuracy early in the symptom course. NS1 ELISA shows similar diagnostic accuracy to RT-PCR, which has important implications for global public health policy, given its relatively low cost and accessibility.

FUNDING

None.

Point-of-care testing: revolutionizing clinical biochemistry using decentralized diagnostics

Point-of-care testing (POCT) refers to decentralized testing done using complex but compact, portable devices that can be done near the site at the patient's bedside. These enable quick diagnosis and timely intervention because turnaround time (TAT) decreases with these devices. They can also be operated by non-medical personnel and patients with minimum expertise as these devices are easy to handle and interpret. This increases patient awareness regarding their diseases and benefits doctors in giving more patient-centered care. POCT devices require minimum setup and can be utilized even in remote places. The present review focuses on POCT devices employed specifically in clinical biochemistry, e.g., glucose, HbA1c, cardiac biomarkers, fertility tests, hematological analysis, electrolytes, enzymes, urine dipstick tests, etc. This introductory review delves into comprehending the fundamentals of POCT technologies, their guidelines, applications, advantages, and disadvantages. It covers a broad overview of the tests done and the samples required to process these tests. It also compares the pros and cons of POCT devices over centralized laboratory testing. The review also aims to emphasize the relevance of its use in today's era, current trends regarding POCT in urban and rural setups, challenges faced in the field during its implementation, and the potential areas of improvement in the future. However, it is advisable to seek references for more detailed and critical information regarding all the specific topics given in this review article.

Machine learning in point-of-care testing: innovations, challenges, and opportunities

The landscape of diagnostic testing is undergoing a significant transformation, driven by the integration of artificial intelligence (AI) and machine learning (ML) into decentralized, rapid, and accessible sensor platforms for point-of-care testing (POCT). The COVID-19 pandemic has accelerated the shift from centralized laboratory testing but also catalyzed the development of next-generation POCT platforms that leverage ML to enhance the accuracy, sensitivity, and overall efficiency of point-of-care sensors. This Perspective explores how ML is being embedded into various POCT modalities, including lateral flow assays, vertical flow assays, nucleic acid amplification tests, and imaging-based sensors, illustrating their impact through different applications. We also discuss several challenges, such as regulatory hurdles, reliability, and privacy concerns, that must be overcome for the widespread adoption of ML-enhanced POCT in clinical settings and provide a comprehensive overview of the current state of ML-driven POCT technologies, highlighting their potential impact in the future of healthcare.

Detection of mpox and other orthopoxviruses using a lateral flow device as a point-of-care diagnostic

In 2022, the World Health Organization declared the worldwide outbreak of mpox to be a public health emergency of international concern. The causative monkeypox virus (MPXV) belonged to clade IIb and is transmitted through sexual contact with a low case fatality rate (0.1%), which, together with under-detection, all contributed to a rapid global spread particularly within the MSM (men who have sex with men) community. As MPXV clade II remains circulating worldwide, a new outbreak of the more fatal clade I disease has been declared in Central and East Africa, and remains uncontrolled in part due to the lack of point-of-care (POC) diagnostics for rapid decisions on treatment and self-isolation. To address the lack of POC solutions for mpox, we have designed and evaluated an orthopoxvirus-specific lateral flow device (LFD) that could be used for the diagnosis of mpox. Using an LFD comprising four monoclonal antibodies against the A27 protein, we demonstrate sensitivity to 3 × 105 pfu/mL. This sensitivity is expected to be sufficient for the detection of MPXV from lesion sites and may also be sufficient for other sample types such as saliva and urine. We found that the presence of guanidinium thiocyanate, a common ingredient in inactivating viral transport media, masked the LFD antigen, resulting in false negatives. POC diagnosis of mpox may be possible using an LFD to reduce delays arising from sample shipment to centralized laboratory testing facilities. In order to achieve this, our work demonstrates that an LFD-optimized buffer is required, as the sample collection buffer may have a detrimental impact on sensitivity for clinical material.IMPORTANCEMpox cases have dramatically increased both in traditionally monkeypox virus endemic countries and also worldwide. This increase comes at a time when immunity derived from smallpox vaccination is no longer available. Diagnosis of mpox is complicated due to both disease presentation and the availability of local diagnostic laboratories. The availability of a point-of-care diagnostic tool such as an lateral flow device (LFD) would play an important role to both diagnose and prevent onward transmission. This manuscript provides developers and assessors with key data for defining true sensitivity and specificity of a successful LFD in addition to buffer conditions for sample collection.

Mass of components and material distribution in lateral flow assay kits

Objective

To assess the type and amount of materials used in commercial lateral flow tests.

Methods

We collected and weighed the components of 21 commercial coronavirus disease 2019 (COVID-19) lateral flow tests from the European Union, the United Kingdom of Great Britain and Northern Ireland, the United States of America and the World Health Organization's emergency use listing procedure. We took test kits apart manually, classified components and weighed them individually.

Findings

We found large variations in the total average weights of the lateral flow kits ranging from 13.7 g per test to 84.6 g. The average weight of standard housing in the kits was 4.1 g per casing (range: 2.8-6.5). The packaging made up between 34% and more than 89% of the whole kit and was found to be a large source of weight variations. In the standard kits, plastics made up on average 36% of the total weight, while paper and cardboard accounted for 52% on average. In the non-standard kits, which had newer cassette designs, the opposite was observed.

Conclusion

Wide variation in the weight of components in COVID-19 tests suggests there is scope for manufacturers to reduce the amount of materials, including plastic, in these products. We propose that a quantitative baseline of material usage be introduced in target product profiles for lateral flow tests to limit the large volume of plastic from reaching the market, and reduce the burden of plastic waste from diagnostic testing on local waste management systems.

The optimal color space enables advantageous smartphone-based colorimetric sensing

Smartphone-based colorimetric (bio)sensing is a promising alternative to conventional detection equipment for on-site testing, but it is often limited by sensitivity to lighting conditions. These issues are usually avoided using housings with fixed light sources, increasing the cost and complexity of the on-site test, where simplicity, portability, and affordability are a priority. In this study, we demonstrate that careful optimization of color space can significantly boost the performance of smartphone-based colorimetric sensing, enabling housing-free, illumination-invariant detection. We evaluated the quantification performance of smartphone-based colorimetry using monotonal shadings of colors with spectral compositions covering a wide range of visible spectra. The color coordinates were extracted from regions of interest (ROI) that were automatically selected using a homemade algorithm. Compared to absorbance-based models, smartphone-based colorimetry offered a broader measurement range with a comparable limit of detection. However, models based on RGB space proved highly sensitive to illumination changes, limiting their reliability. In contrast, the CIELAB color space-specifically the a∗ and b∗ chromatic coordinates-, exhibited inherent resistance to illumination changes. Our concept of equichromatic surfaces explains this inherent resilience to lightning variations, providing a theoretical basis for designing illumination-invariant optical (bio)sensors.

The impact of electronic health records on the ordering of medical tests

BACKGROUND

Healthcare facilities often encounter patients with incomplete records from previous visits, leading to duplicated tests. Recent Electronic Health Records (EHR) investments aim to address this issue. This study examines how viewing patient information via OFEK EHR affects the frequency of tests ordered by the physician. The OFEK system, developed in Clalit Health Services, is an advanced online medical records system used in hospitals. It was expanded to all hospitals and HMOs starting in 2013, allowing medical information to be shared and accessed in the Israeli healthcare system.

METHODS

The study was conducted at the Israel Center for Medical Simulation (MSR), with 26 physicians engaged in encounters with simulated patients (SP). The SPs provided relevant clinical histories and signs for two abdominal pain cases. The physicians ordered diagnostic tests, and after receiving the tests' results they set a final diagnosis and could order additional tests. They had randomized access to the OFEK system to vary test-ordering patterns. In both scenarios, we examined three key variables to see if access to the OFEK system influenced the decision to order diagnostic tests ("QTestsBefore" - the number of tests ordered by the physician after the patient visit; "QTestsAfters" - the number of tests ordered by the physician after receiving the results of the first round; "QSumTests" - The total number of tests).

RESULTS

In the study group with access to the OFEK EHR, an average of 5.5 tests were ordered, compared to 6.85 in the control group (p-value = 0.01). Ordinary Least Squares regressions confirmed that the overall number of tests, particularly the second round ordered after receiving initial results, was significantly lower with OFEK. Additionally, years of clinical practice also correlated with fewer ordered tests.

CONCLUSIONS

The findings show that the OFEK EHR system reduces the number of medical examinations by allowing physicians to access medical histories and past tests, which supports efficient decision-making. This leads to fewer ordered medical tests and, thus, reduces the time procedures patients spend in EDs or hospitals. Efficient decision-making and fewer redundant medical tests can improve patient flow, free up resources, and reduce overcrowding in emergency departments.

Pathogen-Specific Electrochemical Real-Time LAMP Detection Using Universal Solid-Phase Probes on Carbon Electrodes

Epidemic infections and spreading antibiotic resistance require diagnostic tests that can be rapidly adopted. To reduce the usually time-consuming adaptation of molecular diagnostic tests to changing targets, we propose the novel approach of a repurposable sensing electrode functionalization with a universal, target-independent oligonucleotide probe. In the liquid phase covering the electrode, the target sequence is amplified by MD LAMP (mediator-displacement loop-mediated isothermal amplification) releasing a generic methylene blue-labeled mediator, which specifically hybridizes to the solid-phase probe. To demonstrate the universality of the approach, two different pathogens, Staphylococcus aureus (crude lysate) and Treponema pallidum, are detected using the same solid-phase probe. The reactions reach a limit of detection of 1 × 103 and 4 × 102 copies per reaction within 30 min, respectively. The solid-phase probes carry a carboxymethyl aniline modification to form covalent C-C bonds on low-cost carbon electrodes. Maximum surface coverage and maximum hybridization signals are observed at grafting concentrations of ≥2 μM solid-phase probes. Successful detection of spiked target DNA in real swab samples and with three different commercial amplification buffers proved the broad applicability of this assay approach. The electrochemical MD LAMP is fast, compatible with dsDNA targets, and requires only minimal adaptation of an established amplification method. It is easily transferable to existing analytical electrochemical platforms, allowing the consumable to be synergistically used for different targets. The suggested approach of repurposable functionalized electrodes can also be considered to increase the preparedness for future epidemic or pandemic outbreaks as well as rapidly evolving resistance patterns or variants.

Identification and Quantification of Multiple Pathogenic Escherichia coli Strains Based on a Plasmonic Sensor Array

Pathogenic Escherichia coli (E. coli) is a widespread and clinically significant foodborne pathogen. Due to its high mutation rates and phenotypic diversity, rapid identification of its subtypes remains challenging and prone to false positives when detecting single strains. In this study, we developed a plasmonic sensor array with high-dimensional signal readouts (ζ-potential, dynamic light-scattering (DLS), surface-enhanced Raman scattering (SERS), and ultraviolet-visible (UV-vis) absorption spectra) for the selective discrimination of pathogenic E. coli, integrated with bacterial culture methods. The plasmonic sensor units demonstrated strong encoding capabilities, facilitating the differentiation of subtle variations among various E. coli strains and showing excellent anti-interference performance. The array realized different pathogenic E. coli strains, bacterial mixture identification, and even quantitative detection. Remarkably, the working concentration for the sensor array was notably low, at 104 CFU/mL. Finally, by incorporating bacterial isolation culture, the designed sensor array obtained 100% accuracy in detecting E. coli in real food samples. These findings highlight the sensor array's potential for applications in food safety monitoring and clinical diagnostics, offering a sensitive, rapid, and reliable tool for pathogen detection in complex samples.

Recombinase-Controlled Multiphase Condensates Accelerate Nucleic Acid Amplification and CRISPR-Based Diagnostics

Isothermal techniques for amplifying nucleic acids have found extensive applications in genotyping and diagnostic tests. These methods can be integrated with sequence-specific detection strategies, such as CRISPR-based detection, for optimal diagnostic accuracy. In particular, recombinase-based amplification uses proteins from the Escherichia virus T4 recombination system and operates effectively at moderate temperatures in field and point-of-care settings. Here, we discover that recombinase polymerase amplification (RPA) is controlled by liquid-liquid phase separation, where the condensate formation enhances the nucleic acid amplification process. While two protein components of RPA could act as scaffold proteins for condensate formation, we identify T4 UvsX recombinase as the key regulator orchestrating distinct core-shell arrangements of proteins within multiphase condensates, with the intrinsically disordered C-terminus of UvsX being crucial for phase separation. We develop volumetric imaging assays to visualize RPA condensates and the reaction progression in whole volumes, and begin to dissect how macroscopic properties such as size distribution and droplet count could contribute to the overall reaction efficiency. Spatial organization of proteins in condensates may create optimal conditions for amplification, and disruption of such structures may diminish the amplification efficiency, as we demonstrate for the case of reverse transcription-RPA. The insight that RPA functions as a multiphase condensate leads us to identify the UvsXD274A mutant, which has a distinct phase-separation propensity compared to the wild-type enzyme and can enhance RNA detection via RPA-coupled CRISPR-based diagnostics.

Portable molecular diagnostic platform for rapid point-of-care detection of mpox and other diseases

The World Health Organization's designation of mpox as a public health emergency of international concern in August 2024 underscores the urgent need for effective diagnostic solutions to combat this escalating threat. The rapid global spread of clade II mpox, coupled with the sustained human-to-human transmission of the more virulent clade I mpox in the Democratic Republic of Congo, highlights a critical gap in point-of-care diagnostics for this emergent disease. In response, we developed Dragonfly, a portable molecular diagnostic platform for point-of-care use that integrates power-free nucleic acid extraction (<5 minutes) with lyophilised colourimetric LAMP chemistry. The platform demonstrated an analytical limit-of-detection of 100 genome copies per reaction for monkeypox virus, effectively distinguishing it from other orthopoxviruses, herpes simplex virus, and varicella-zoster virus. Clinical validation on 164 samples, including 51 mpox-positive cases, yielded 96.1% sensitivity and 100% specificity for orthopoxviruses, and 94.1% sensitivity and 100% specificity for monkeypox virus. Here, we present a rapid, accessible, and robust point-of-care diagnostic solution for mpox, suitable for both low- and high-resource settings, addressing the global resurgence of orthopoxviruses in the context of declining smallpox immunity.

Nanoparticle-protein corona enhances accuracy of Ca-19.9-based pancreatic cancer classification

Among the various types of pancreatic cancers, pancreatic ductal adenocarcinoma (PDAC) is the most lethal and aggressive, due to its tendency to metastasize quickly and has a particularly low five-year survival rate. Carbohydrate antigen 19-9 (CA 19-9) is the only biomarker approved by the Food and Drug Administration for PDAC and has been a focal point in diagnostic strategies, but its sensitivity and specificity are not sufficient for early and accurate detection. To address this issue, we introduce a synergistic approach combining CA 19-9 levels with a graphene oxide (GO)-based blood test. This non-invasive technique relies on the analysis of personalized protein corona formed on GO sheets once they are embedded in human plasma. Pairing CA 19-9 values with GO protein patterns from N = 106 donors significantly improved the ability to differentiate between non-oncological and PDAC patients (up to 92%), also boosting the classification of PDAC subjects by 50% compared to CA 19-9 testing alone. Overall, this study sought to bridge the existing gaps in PDAC detection by exploiting the complementary strengths of conventional biomarkers and cutting-edge nanotechnology. Exploration of this combined strategy holds promise for advancing the early detection of PDAC, ultimately contributing to improved patient prognosis and treatment outcomes.

Immunoelectrochemical assessment of human IgE in non-invasive samples of allergic individuals using PdNCs-labelled antibodies

The escalating global prevalence of allergies presents a substantial public health challenge. Immunoglobulin E (IgE) serves as a key biomarker for allergic diseases, often measured in blood serum by ELISA immunoassays. Despite recent interest in minimally invasive sampling of biological fluids, the low sample volumes and IgE concentrations demand highly sensitive methodologies, typically confined to centralized laboratories. In this article, a decentralizable approach based on competitive immunoassays using Pd nanocluster (PdNCs)-labelled antibodies for electrochemical detection is proposed. With this aim, PdNCs were successfully bioconjugated with an anti-hIgE antibody to perform competitive immunoassays. To improve the analytical capabilities of the methodology, disposable screen-printed carbon electrodes with dual working electrodes were used for enhancing precision. Prior electrodeposition of PdNCs at - 0.6 V for 90 s significantly improved sensitivity (7.1 µA g ng⁻1) and lowered the limit of detection (LoD) to 0.3 ng g⁻1 for PdNCs determination. The use of PdNCs as labels resulted in an improvement in the LoD for IgE determination. Calibration curves performed using competitive immunoassays for IgE determination, ranging from 10-5 to 102 ng g-1, demonstrated sensitivity comparable to high-tech methods, with a LoD of 0.008 ng g-1 for electrochemical measurements. Bimodal detection of Pd (linear sweep voltammetry and inductively coupled plasma-mass spectrometry) in various biological fluids (saliva, tears, nasal exudate, capillary blood, and blood serum) revealed significant differences in IgE levels between allergic and non-allergic individuals. Notably, capillary blood correlated strongly with serum blood, and a certain correlation has also been found with nasal exudate. The electrochemical approach, combining sensitivity and precision with non-invasive sampling, offers a simplified alternative for IgE determination in allergic disease.

Equipmentless point-of-care testing of dengue antibodies using ELISA and smartphones

Infections with the dengue virus affect more than 100 million people every year. The infected can present a mild form of the disease or a severe form, which can, eventually, lead to death. Dengue prevails in tropical and subtropical regions, although increased incidence has been observed in the last years in tempered climates. Vaccines are available but testing for previous infection is often required prior to application. Commercially available ELISA and rapid tests for the diagnosis of dengue IgG do not fulfill individually the performance required by control agencies. In this context, rapid, simple and decentralized point-of-care testing (POCT) is highly desirable. However, POCT approaches available usually offer expensive solutions, often due to the complex complementary hardware required. In this article, an equipmentless system based on a commercial ELISA kit and a smartphone is developed for POCT of dengue antibodies. A customized app provides guiding, optical reading, result reporting and connectivity. The reading method employes an algorithm which requires no external information, other than the available on the digital images from the smartphone camera, to classify samples into positives, negatives or indeterminates. The full system operation, from sample extraction to result reporting, was tested in a low resource medical facility with real patients (n = 26). After comparison with an ELISA reader, a Cohen's κ coefficient of 0.92 was obtained, showing very good agreement between both methods. These results show that it is possible to perform ELISA with no specific equipment, bringing massive testing at low resource facilities one step closer.

Diagnostic accuracy of an antigen-based point-of-care test versus nucleic acid amplification testing for genital trichomoniasis among pregnant women attending antenatal care facilities in Zambia

BACKGROUND

Infection with Trichomonas vaginalis (TV) is the most prevalent curable sexually transmitted infection (STI) globally and is associated with prelabour rupture of membranes, preterm delivery, and low birthweight. Point-of-care (POC) testing for TV during pregnancy may facilitate rapid antenatal case detection and treatment. This study, part of the World Health Organization's global ProSPeRo study, aimed to evaluate the performance of OSOM® Trichomonas Rapid Test, an antigen-based POC test, against a reference nucleic acid amplification test (NAAT) among pregnant women in Zambia. We also assessed the operational characteristics and patient acceptability of the POC test, within the context of WHO's target product profiles for STI POC tests.

METHODS

We enrolled pregnant women attending four health centres in Nchelenge, Zambia, for antenatal care between 15 February and 26 May 2023. Vaginal swabs for the TV POC test and a reference NAAT (Aptima® Trichomonas vaginalis assay) were obtained. POC test results were read independently by two study staff members. Study staff filled a questionnaire on the operational characteristics of the POC test, and participants were asked about their willingness to wait for results.

RESULTS

Paired POC and reference test samples were collected from 1,015 participants. Overall, 23.0% (233/1015) tested positive for TV by NAAT, and 15.3% (155/1015) tested positive by the POC test, with three inconclusive results. The overall sensitivity and specificity of the POC test were 66.4% (95% confidence intervals [CI] 57.7-74.1%) and 99.6% (95% CI: 98.8-99.9%), respectively. Sensitivity was higher among those with TV-associated symptoms compared to those without (83.6% versus 60.4%, relative ratio 1.39, 95% CI 1.14-1.68). Inter-rater agreement was 99.7% (Cohen's Kappa 0.989). The study staff (n = 14) found the test easy to use and interpret, with most staff (12/14) reporting results were available within 25 min.

CONCLUSION

Overall, the TV POC test showed lower sensitivity than WHO's 85% target, but exceeded the 99% specificity target. Among symptomatic pregnant women, sensitivity nearly reached the WHO target. The assay was user-friendly, required minimal training, and delivered results quickly. Further studies are needed to determine the optimal antenatal settings for this technology.

TRIAL REGISTRATION

PACTR202302766902029.

Autoimmune cardiac channelopathies and heart rhythm disorders: A contemporary review

Cardiac arrhythmias still represent a major health problem worldwide, at least in part because the fundamental pathogenic mechanisms are not fully understood, thus affecting the efficacy of therapeutic measures. In fact, whereas cardiac arrhythmias are in most cases due to structural heart diseases, the underlying cause remains elusive in a significant number of patients despite intensive investigations even including postmortem examination and molecular autopsy. A large body of data progressively accumulated during the last decade provides strong evidence that autoimmune mechanisms may be involved in a significant number of such unexplained or poorly explained cardiac arrhythmias. Several proarrhythmic anti-cardiac ion channel autoantibodies have been discovered, in all cases able to directly interfere with the electrophysiologic properties of the heart but leading to different arrhythmic phenotypes, including long QT syndrome, short QT syndrome, and atrioventricular block. These autoantibodies, which may develop independent of a history of autoimmune diseases, could help explain a percentage of arrhythmic events of unknown origin, thereby opening new frontiers for diagnosis and treatment of heart rhythm disorders. Based on this evidence, the novel term autoimmune cardiac channelopathies was coined in 2017. Since then, the interest in the field of cardioimmunology has shown a tumultuous growth, so much so that the number of arrhythmogenic anti-ion channel autoantibodies reported has significantly increased, also in association with not previously described arrhythmic phenotypes, such as atrial fibrillation, Brugada syndrome, and ventricular fibrillation/cardiac arrest. Thus, an updated reassessment of this topic, also highlighting perspectives and unmet needs, has become necessary and represents the main objective of this review.

Toward a rapid, sensitive, user-friendly, field-deployable artificial intelligence tool for enhancing African swine fever diagnosis and reporting

Objective

African swine fever (ASF) is a lethal and highly contagious transboundary animal disease with the potential for rapid international spread. Lateral flow assays (LFAs) are sometimes hard to read by the inexperienced user, mainly due to the LFA sensitivity and reading ambiguities. Our objective was to develop and implement an AI-powered tool to enhance the accuracy of LFA reading, thereby improving rapid and early detection for ASF diagnosis and reporting.

Methods

Here, we focus on the development of a deep learning-assisted, smartphone-based AI diagnostic tool to provide accurate decisions with higher sensitivity. The tool employs state-of-the-art You Only Look Once (YOLO) models for image classification. The YOLO models were trained and evaluated using a dataset consisting of images where the lateral flow assays are manually labeled as positives or negatives. A prototype JavaScript website application for ASF reporting and visualization was created in Azure. The application maintains the distribution of the positive predictions on a map as the positive cases are submitted by users.

Results

The performance of the models is evaluated using standard evaluation metrics for classification tasks, specifically accuracy, precision, recall, sensitivity, specificity, and F1 measure. We acquired 86.3 ± 7.9% average accuracy, 96.3 ± 2.04% average precision, 79 ± 13.20% average recall, and an average F1 score of 0.87 ± 0.088 across 3 different train/development/test splits of the datasets. Submitting a positive result of the deep learning model updates a map with a location marker for positive results.

Conclusions

Combining clinical data learning and 2-step algorithms enables a point-of-need assay with higher accuracy.

Clinical Relevance

A rapid, sensitive, user-friendly, and deployable deep learning tool was developed for classifying LFA test images to enhance diagnosis and reporting, particularly in settings with limited laboratory resources.

Enhanced Chlamydia trachomatis and Neisseria gonorrhoeae Sexually Transmitted Infections and Associated Risk Factors in Fiji Following the Coronavirus Disease 2019 Pandemic

Background

The coronavirus disease 2019 pandemic impact on sexually transmitted infections in countries practicing syndromic management remains unknown. We conducted cross-sectional surveys in Fiji to assess increases and risk factors for Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) infections pre- and postpandemic.

Methods

We enrolled women, men who have sex only with women (MSW), and men who have sex with men (MSM) aged 18-40 years, collected sociodemographic/behavioral data, and tested vaginal, urethral, and rectal samples using Xpert-CT/NG. Risk factors were evaluated using regression models.

Results

Of 1955 participants, 6.4% (95% confidence interval [CI], 5.4%-7.6%) had gonorrhea, increasing significantly postpandemic >2-fold among women aged 25-40 years and >4-fold among MSM, MSW, and men aged 18-24 and 25-40 years; 20.0% (95% CI, 18.3%-21.8%) had chlamydia, increasing significantly postpandemic among younger women and approximately 2- to 4-fold among MSW and younger and older men. Increases were driven by urethral/vaginal infections. Coinfections increased significantly postpandemic among older women. Postpandemic gonorrhea was associated with difficulty obtaining condoms (adjusted relative risk [aRR], 2.7 [95% CI, 1.0-8.0]) and ≥2 partners (aRR, 2.6 [95% CI, 1.0-7.1]) among younger women, and iTaukei ethnicity (aRR, 4.7 [95% CI, 1.4-16.5]) and heavy alcohol use (aRR, 7.1 [95% CI, 2.5-19.7]) among older women. Postpandemic chlamydia was associated with having a casual sex partner among younger (aRR, 1.7 [95% CI, 1.0-2.9]) and older (aRR, 1.9 [95% CI, 1.1-3.4]) women and with being unmarried (aRR, 1.7 [95% CI, 1.0-2.7]). iTaukei men had increased risk postpandemic for gonorrhea (aRR, 3.7 [95% CI, 1.3-10.6]) and chlamydia (aRR, 2.5 [95% CI, 1.3-4.9]). More than 50% of infected participants did not meet syndromic treatment criteria and would have remained untreated.

Conclusions

Postpandemic increases in gonorrhea and chlamydia-with risk factors varying by pathogen, gender, and age-require immediate interventions to reduce infection and transmission in Fiji.

Wastewater-borne viruses and bacteria, surveillance and biosensors at the interface of academia and field deployment

Wastewater is a complex, but an ideal, matrix for disease monitoring and surveillance as it represents the entire load of enteric pathogens from a local catchment area. It captures both clinical and community disease burdens. Global interest in wastewater surveillance has been growing rapidly for infectious diseases monitoring and for providing an early warning of potential outbreaks. Although molecular detection methods show high sensitivity and specificity in pathogen monitoring from wastewater, they are strongly limited by challenges, including expensive laboratory settings and prolonged sample processing and analysis. Alternatively, biosensors exhibit a wide range of practical utility in real-time monitoring of biological and chemical markers. However, field deployment of biosensors is primarily challenged by prolonged sample processing and pathogen concentration steps due to complex wastewater matrices. This review summarizes the role of wastewater surveillance and provides an overview of infectious viral and bacterial pathogens with cutting-edge technologies for their detection. It emphasizes the practical utility of biosensors in pathogen monitoring and the major bottlenecks for wastewater surveillance of pathogens, and overcoming approaches to field deployment of biosensors for real-time pathogen detection. Furthermore, the promising potential of novel machine learning algorithms to resolve uncertainties in wastewater data is discussed.

Cell-free DNA as a complementary diagnostic tool for neglected tropical diseases towards achieving the WHO NTDs elimination by 2030

Neglected Tropical Diseases (NTDs) continue to ravage the poorest regions of the world, with over 600 million people being affected in Sub-Saharan Africa. The global burden of NTDs within these regions is staggering, particularly post-COVID-19 pandemic, where the emerging infection intercepted the existing eradication efforts and protocols such as the Mass Drug Administration (MDA). This further complicated the approaches laid down to achieve the endgame program of eliminating the neglect and transmission of NTDs. To compensate for the detriment of COVID-19's interruption, accurate and timely diagnoses play a vital role in attaining the objectives of the WHO's goal of NTD elimination by 2030. To this effect, alternative approaches in diagnostics are urgently needed, particularly with the inadequacy of current diagnostic strategies for NTDs. Cell-free DNA (cfDNA) has shown great promise in detecting NTDs. Several studies have demonstrated its potential for diagnosing diseases such as malaria, leishmaniasis, and schistosomiasis. However, the adoption of cfDNA in NTD research faces several challenges, including the cost of the procedure, standardization, and technical expertise. Proper capacity building and training can mitigate some of these challenges. However, despite these limitations, the affordability of cfDNA detection is improving due to increased awareness of the approach and researchers' integration considerations into current diagnostic routines. In conclusion, while there are challenges to adopting cfDNA in NTD research, it remains a promising alternative strategy to be considered in the fight against NTDs.

Single-tube detection of a foodborne bacterial pathogen using user-friendly portable device

Timely and reliable detection of foodborne bacterial pathogen is crucial for reducing disease burden in low- and middle-income countries. However, laboratory-based methods are often inaccessibility in resource-limited settings. Here, we developed a single-tube assay and a low-cost palm-sized device for on-site detection of the representative foodborne bacterial pathogen, Salmonella Enteritidis. Our assay incorporates the advantages of protein-nucleic acid signal transduction, EXPonential Amplification Reaction (EXPAR), and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 12a (Cas12a). After systematically investigating the compatibility of these components, we developed a "three-in-one" integration reaction, termed ST-EXPAR-CRISPR assay. This assay requires only one tube, one controlled temperature (39 °C) and simple operation, eliminating the need for bacterial isolation, nucleic acid extraction, or washing steps. ST-EXPAR-CRISPR assay is capable of detecting as few as 37 CFU/mL of target bacterium. Using our kit and portable device, untrained volunteers successfully detected contamination in food samples outdoors. The simplicity of the detection process and minimal hardware requirements make our assay highly promising for application in point-of-care and on-site scenarios. Moreover, the ST-EXPAR-CRISPR assay can be easily modified to detect other targets by changing the nucleic acid sequence with low research and development cost, potentially reducing the global disease burden.

Establishing quality assurance for COVID-19 antigen tests in the Indo Pacific Region: A multi-site implementation study

BACKGROUND

Quality assurance programs (QAPs) are used to evaluate the analytical quality of a diagnostic test and provide feedback to improve quality processes in testing. Rapid diagnostic tests were used in both laboratory and non-laboratory settings to diagnose COVID-19, although varied in reported performance. We aimed to design and implement a QAP for antigen rapid diagnostic tests (Ag-RDTs) for COVID-19 in Cambodia, Lao PDR, and Papua New Guinea.

METHODS

Inactivated SARS-CoV-2 material derived from cell culture of Wildtype, Delta, and Omicron isolates were used to manufacture 435 quality control (QC) panels (consisting of a single positive and negative sample) and 36 external quality assessment (EQA) panels for use across 15 sites in accordance with provided training and protocols.

RESULTS

In total, 369 QC results and 112 EQA results were submitted by electronic reporting or paper forms by two countries. 19·3 % (34/176) positive and 99·5 % (192/193) negative samples were correctly reported in the QC, and 37·5 % (30/80) positive and 97·5 % (39/40) negative samples were correctly reported in the EQA.

CONCLUSION

This QAP demonstrates the importance of operator training and the design of QAP materials, which may have contributed to the high rate of false-negative interpretations in known COVID-19 positive samples. The implementation of this project, to our knowledge the first of its kind in the region and one of only a few globally, emphasised the importance of quality assurance principles, including non-laboratory community testing sites, to promote diagnostic quality for COVID-19 testing.

Colorimetric CRISPR Biosensor: A Case Study with Salmonella Typhi

There is a critical need to implement a sensitive and specific point-of-care (POC) biosensor that addresses the instrument limitations and manufacturing challenges faced in resource-constrained contexts. In this paper we focus on enteric fever which is a highly contagious and prevalent infection in low- and middle-income countries. Although easily treatable, its ambiguous symptoms paired with a lack of fast, accurate and affordable diagnostics lead to incorrect treatments which exacerbate the disease burden, including increasing antibiotic resistance. In this study, we develop a readout module for CRISPR-Cas12a that produces a colorimetric output that is visible to the naked eye and can act as a cascade signal amplifier in any CRISPR assay based on trans-cleavage. We achieve this by immobilizing an oligo covalently linked to a β-galactosidase (LacZ) enzyme, which is cleaved in the presence of DNA target-activated CRISPR-Cas12a. Upon cleavage, the colorimetric enzyme is released, and the supernatant transferred to an environment containing X-Gal producing an intense blue color. This method is capable of detecting amplified bacterial genomic DNA and has a lower limit of detection (LoD) to standard fluorescent assays while removing the requirement for costly equipment. Furthermore, it remained active 4 weeks after lyophilization, allowing for the possibility of shipment without cold chain, significantly reducing deployment costs.

Development and Validation of a Combined RT-LAMP Assay for the Rapid and Sensitive Detection of Dengue Virus in Clinical Samples from Colombia

Background: Dengue virus (DENV) infection is a significant public health concern in several tropical and subtropical regions, where early and rapid detection is crucial for effective patient management and controlling the spread of the disease. Particularly in resource-limited, rural healthcare settings where dengue is endemic, there exists a need for diagnostic methods that are both easy to perform and highly sensitive. Objective: This study focuses on the development and validation of a single-tube reverse transcription loop-mediated isothermal amplification termed TURN-RT-loop-mediated isothermal amplification (LAMP) for the detection of DENV. Methodology: The TURN-RT-LAMP assay designed in this study combines two sets of primers targeting the 5'- and 3'-UTR of DENV, with the aim to increase the sensitivity of detection. Results: Clinical validation of the TURN-RT-LAMP assay using samples collected from febrile individuals with a serological or antigenic diagnosis revealed a sensitivity of >96%. The performance of this assay was statistically compared with that of the standard diagnostic method, quantitative reverse transcription-polymerase chain reaction. Conclusions: The results support the potential of RT-LAMP as a rapid, sensitive, and specific tool for the diagnosis and surveillance of dengue, particularly suitable for field use in low-resource settings.

Point-of-need diagnostics in a post-Covid world: an opportunity for paper-based microfluidics to serve during syndemics

Zoonotic outbreaks present with unpredictable threats to human health, food production, biodiversity, national security and disrupt the global economy. The COVID-19 pandemic-caused by zoonotic coronavirus, SARS-CoV2- is the most recent upsurge of an increasing trend in outbreaks for the past 100 years. This year, emergence of avian influenza (H5N1) is a stark reminder of the need for national and international pandemic preparedness. Tools for threat reduction include consistent practices in reporting pandemics, and widespread availability of accurate detection technologies. Wars and extreme climate events redouble the need for fast, adaptable and affordable diagnostics at the point of need. During the recent pandemic, rapid home tests for SARS-CoV-2 proved to be a viable functional model that leverages simplicity. In this perspective, we introduce the concept of syndemnicity in the context of infectious diseases and point-of-need healthcare diagnostics. We also provide a brief state-of-the-art for paper-based microfluidics. We illustrate our arguments with a case study for detecting brucellosis in cows. Finally, we conclude with lessons learned, challenges and opportunities for paper-based microfluidics to serve point-of-need healthcare diagnostics during syndemics.

Recent Advances in Biosensor Technologies for Meat Production Chain

Biosensors are innovative and cost-effective analytical devices that integrate biological recognition elements (bioreceptors) with transducers to detect specific substances (biomolecules), providing a high sensitivity and specificity for the rapid and accurate point-of-care (POC) quantitative detection of selected biomolecules. In the meat production chain, their application has gained attention due to the increasing demand for enhanced food safety, quality assurance, food fraud detection, and regulatory compliance. Biosensors can detect foodborne pathogens (Salmonella, Campylobacter, Shiga-toxin-producing E. coli/STEC, L. monocytogenes, etc.), spoilage bacteria and indicators, contaminants (pesticides, dioxins, and mycotoxins), antibiotics, antimicrobial resistance genes, hormones (growth promoters and stress hormones), and metabolites (acute-phase proteins as inflammation markers) at different modules along the meat chain, from livestock farming to packaging in the farm-to-fork (F2F) continuum. By providing real-time data from the meat chain, biosensors enable early interventions, reducing the health risks (foodborne outbreaks) associated with contaminated meat/meat products or sub-standard meat products. Recent advancements in micro- and nanotechnology, microfluidics, and wireless communication have further enhanced the sensitivity, specificity, portability, and automation of biosensors, making them suitable for on-site field applications. The integration of biosensors with blockchain and Internet of Things (IoT) systems allows for acquired data integration and management, while their integration with artificial intelligence (AI) and machine learning (ML) enables rapid data processing, analytics, and input for risk assessment by competent authorities. This promotes transparency and traceability within the meat chain, fostering consumer trust and industry accountability. Despite biosensors' promising potential, challenges such as scalability, reliability associated with the complexity of meat matrices, and regulatory approval are still the main challenges. This review provides a broad overview of the most relevant aspects of current state-of-the-art biosensors' development, challenges, and opportunities for prospective applications and their regular use in meat safety and quality monitoring, clarifying further perspectives.