Point-of-care Testing Research Articles

Graphene electrochemical biosensors combining effervescent solid-phase extraction (ESPE) for rapid, ultrasensitive, and simultaneous determination of DA, AA, and UA

Simultaneous monitoring of key metabolites like dopamine, ascorbic acid, and uric acid is essential for early disease diagnosis and evaluating treatment. Electrochemical techniques are increasingly used for precise, point-of-care testing (POCT) of these metabolites. Herein, a sample pretreatment method called effervescent solid-phase extraction (ESPE) was proposed for efficient enrichment of trace analytes for electrochemical detection. In an ESPE process, effervescent tablets made of gold nanoparticle-decorated graphene oxide (Au/GO) were first self-dispersed in a test solution to promote the enrichment of analytes on the Au/GO adsorbents, followed by the addition of flocculant effervescent tablets to cause Au/GO sheets to form self-assembled aggregates, which then can be efficiently collected by the foam electrodes. The entire sample pretreatment process operates without external power and takes only 5 min. With the assistance of the ESPE method, our electrochemical sensors achieve an ultralow detection limit for dopamine, ascorbic acid, and uric acid of 80 pM, 1.8 nM, and 460 pM, respectively, which are two to three orders of magnitude lower than the results obtained by the drop casting technique. The enhancement mechanism of our approach is based on increasing the contact probability with analytes through dynamic dispersion of the Au/GO adsorbents, in contrast to the static diffusion mechanism relied on Brownian motion. We also show that combining the ESPE solution kit with a portable micro-electrochemical workstation can attain the same detection level as HPLC in real urine samples. The proposed ESPE approach holds great promise for POCT applications in 2D material-based biosensors.

Performance of an Oral Rinse Point-Of-Care Assay to aid in the diagnosis of Head and Neck Squamous Cell Carcinoma (HNSCC) in a High-Risk Danish Ear-Nose Throat (ENT) Clinic

Abstract Objectives Oral examination and biopsy are established methods for early detection of oral/oropharyngeal squamous cell carcinoma (OOSCC). The aim of the current study was to evaluate performance of a point-of-care (POC) assay to aid in the diagnosis of head and neck cancer. Materials and methods 150 consecutive patients were enrolled from a high-risk ear nose and throat clinic at the Rigshospitalet in Copenhagen, Denmark. A positive POC test represented as a CD44 band or elevated level of total protein (TP) was correlated with biopsy results and then evaluated with sensitivity (Se), specificity (Sp), PPV, NPV and multivariate models. Results 119 patients enrolled between January 2016 and April 2017. Presence of a CD44 band or TP ≥3: Se of 73% (95% CI 57.0–84.6%), Sp of 50% (95% CI 39.4–60.5%), and NPV of 94.77% (95% CI 84.12–98.33%). CD44 band or TP of ≥ 2 for non-smkers and ≥ 3 for smokers improved performance: Se 81% (95%CI 66–90%) and Sp 33% (95%CI 24–44%), NPV of 94%. Multivariate models with male gender and ≥ 60 years: Se of 84% (95%CI 67–92%) and Sp of 37% (95%CI 27–47%), NPV of 95%. Non-biopsied, healthy, non-smoking, females (n = 17): Sp of 78%. Conclusions POC assay performed well for identifying OOSCC in a prospective clinical trial. Clinical features such as age, smoking status and gender are important variables in assessing risk. Additional studies are underway to further confirm these results including the incorporation of a version 2 POC device.

Geographical Access to Point-of-care diagnostic tests for diabetes, anaemia, Hepatitis B, and human immunodeficiency virus in the Bono Region, Ghana

BackgroundDiabetes mellitus, human immunodeficiency virus (HIV), hepatitis B and anaemia are major global public health issues according to the World Health Organization (WHO). Access to diagnostic testing is essential for their prompt detection and treatment. The WHO has recommended a list of essential in-vitro diagnostics for testing at all levels of care. However, a survey preceding this study showed limited availability of point-of-care (POC) tests for these conditions in the Bono Region (BR) of Ghana. This study assessed the geographical access to diabetes, anaemia, hepatitis B, and HIV POC testing in the BR, Ghana for targeted improvement.MethodsWe gathered the geolocated data of 137 facilities (CHPS, Clinics, healthcare centres, and hospitals) in the BR that were providing glucose, haemoglobin (Hb), Hepatitis B Surface Antigen (Hep B), and HIV POC testing services in July 2022. We used ArcGIS 10.1 to quantify the geographical access (distance and travel time) to the nearest available testing site for each test and show places with inadequate access, for targeted improvement. The journey time was calculated assuming a speed of 20 kilometres (km)/h. ArcMap 10.1 was employed to run spatial autocorrelation (Moran Index (MI)) to determine the spatial distribution of the facilities providing the tests investigated.ResultsOf the 137 facilities, the glucose test was available in 67 (49%), the Hb test in 55 (40%), the Hep B test in 44 (32%), and the HIV test in 73 (53%). The mean (standard deviation (SD)) for obtaining glucose tests in the region was 7.4 ± 3.7 km, Hb was 8.1 ± 4.06 km, Hep B was 8.2 ± 4.1 km, and HIV test was 7.3 ± 3.7 km by a motorised cycle. The mean SD travel time in the region to obtain the glucose test was 94.4 ± 47.2 min compared to 95.7 ± 47.8 min for Hb, 95.9 ± 47.93 min for Hep B, and 92.7 ± 46.3 min for the HIV test. Three districts (Berekum East, Dormaa East, and Jaman North) recorded shorter distances (< 10 km) and a shorter travel time to the glucose, Hb, Hep B, and HIV tests compared to the Banda district, which recorded more than 10 km for all tests investigated. Positive IM values were recorded for all the POC tests, suggesting that the health facilities providing the glucose, Hb, Hep B, and HIV tests in the BR were spatially distributed at random.ConclusionsThe findings revealed moderate access to all the tests in districts across the region. However, geographical access to glucose, Hb, Hep B, and HIV POC testing was poor (distance ≥ 10 km and travel time of ≥ 93 min), in the Banda district. This study showed the need to prioritise the Banda district for targeted improvement for all the tests. A further study is recommended to identify potential solutions to addressing the POC testing implementation in the BR, as demonstrated by this study.

A national survey of first line antibiotic use in neonatal units - and the potential scope for iatrogenic sensorineural hearing loss prevention.

National Institute for Clinical Excellence (NICE) guidance for the management of neonatal sepsis recommends a first-line antibiotic regimen containing an aminoglycoside (gentamicin). Aminoglycoside exposure causes sensorineural hearing loss in individuals with a specific mitochondrial genetic variant (m.1555A>G). This variant can be detected promptly (in <30 min) by a point of care test. NICE does allow for variation in antibiotic regimes depending on local microbiology guidance. As practices can vary, this survey aimed to determine the current use of first-line antibiotic agents within neonatal units and postnatal wards across the UK. A telephone survey was conducted across all neonatal units in the United Kingdom. Responses were requested from a member of the neonatal team experienced in neonatal septic screening processes. One response was recorded per unit. Of the 187 neonatal units, 186 (99%) responded to the survey. One unit declined to participate. The survey results show most neonatal units (93%) and postnatal wards (74%) across the United Kingdom use aminoglycosides as first-line antibiotic agents. Antibiotic regimes varied between different units and between different locations within the same hospital (NICU vs. postnatal wards). In cases where there was a contraindication to aminoglycosides, the most common alternative antibiotic was cefotaxime. Most neonatal units in the UK use an aminoglycoside antibiotic as first-line agent for suspected sepsis. This places infants with the m.1555A>G genetic variant at risk of iatrogenic hearing loss. There needs to be integration of point-of-care genetic testing within the neonatal septic screening pathway.

Enzyme-encapsulated metal-organic framework ZIF-8-mediated biosensor for ultrasensitive detection of urinary prostatic exosomal protein using a glucose meter.

A highly sensitive and efficient home-use method is impressive and promising in the self-monitoring of chronic prostatitis (CP). Herein, we developed a glucose oxidase-zeolitic imidazolate framework-8-antibody composite (GOx@ZIF-8@Ab2) to achieve highly sensitive point-of-care testing (POCT) of urinary prostatic exosomal protein (PSEP) by combining it with a personal glucometer (PGM). The developed GOx@ZIF-8@Ab2 was prepared through a simple but effective biomineralization reaction and a strong binding affinity between Zn2+ and Fc region of the antibody. This bifunctional material GOx@ZIF-8@Ab2 could not only specifically recognize the PSEP via immunoreaction but also wrap a large number of GOx molecules. Following the sandwich immunoreaction, the prepared GOx@ZIF-8@Ab2 facilitated hydrolysis of glucose in a one-to-many fashion, amplifying the detection signal and greatly improving the sensitivity of PGM detection. In comparison to those of the conventional enzyme-linked immunosorbent assay (ELISA), the detection time of the developed technique was shortened to 45 minutes and its limit of detection (0.23 pg mL-1) was reduced by 4-5 orders of magnitude. This technique was successfully utilized for detecting PSEP in human urine samples with a recovery rate of 96-116%. Owing to its rapid, ultrasensitive, specific and portable features, the as-designed platform based on GOx@ZIF-8@Ab2 and the PGM device holds great promise as a home-use POCT platform for self-monitoring of CP and other chronic diseases.

Persistent chemiluminescence-based nanosensor for portable point-of-care testing of H2O2.

Anovel glow-type chemiluminescence (CL)-based nanosensing system was developed for sensitive and rapid point-of-care testing (POCT) of H2O2 in food. CuSe nanoparticles (CuSeNPs) have excellent peroxidase-like activity. After being modified with thiols of 4-mercaptophenylboronic acid (MBA) (CuSeNPs@MBA), luminol can be catalyzed to produce long-lasting CL in the presence of H2O2. The possible reason for the long-lasting glow-type CL behavior was explored. Under the optimized condition, H2O2 can be sensitively detected with improved repeatability. The limit of detection isas low as 0.30 μM. To meet the requirement of in situ and outside of laboratory detection, a 3D-printed portable device was designed which can eliminate the environmental interference to improve detection accuracy. The developed multifunctional platform also has the advantages of simple operation and low cost, suggesting its great potential for applications in food and agricultural fields.

Distance-Based Fluorescent Immunosensor for Point-of-Care Test of Illegal Additives through the Gas-Producing Nanozyme.

The colorimetric point-of-care test (POCT) offers a rapid and efficient method for detecting specific targets in real samples. However, traditional colorimetric methods often rely on complex signal amplification techniques or electronic devices to enhance detection sensitivity, which can inadvertently increase both cost and time, thus contradicting the fundamental goals of visual detection methods. Here, we presented a distance-based fluorescent immunosensor that utilized a gas-producing nanozyme for continuous gas production reaction as a signal. Specifically, the SOM-ZIF-8@Pt nanozyme catalyzed the production of O2 from H2O2 to cause an obvious increase in the pressure within a sealed chamber, thus driving the production of H2S to quench the fluorescence of CsPbBr3 on the walls of the capillaries. Based on the competitive immunoassay, the fluorescence quenching lengths were relative with the concentration of aminopyrine in the range from 0.2 to 20 ng/L; thus, the fluorescent POCT-based homemade device was realized through the amplification of distance-based signals facilitated by the continuous gas production reaction. This strategy provides an effective way to realize POCT assays in resource-limited areas by transforming pressure variations into directly observable signals. Furthermore, distinguished by its high sensitivity, ease of operation, and portability, it also represents a significant advancement in biomedical diagnostics, particularly within home healthcare and clinical POCT.

Comparison of rapid test for high-sensitivity troponin I with laboratory high-sensitivity troponin T in patients with acute chest pain - a prospective monocentric study

Abstract Background and purpose High-sensitivity troponin (hs-Tn) assays are recommended for routine clinical use for diagnosis of acute coronary syndrome (ACS). However, laboratory hs-TnT can be elevated due to non-cardiac conditions, such as pulmonary embolism, skeletal muscle injury or chronic kidney disease. The aim of our study was to compare the diagnostic accuracy of the bed-side rapid hs-troponin I (hs-TnI) assay with hs-TnT measured by routine laboratory. Methods This prospective monocentric study was conducted at a tertiary hospital outpatient cardiac unit with an emergency clinic for patients with acute symptoms. A total of 129 patients were included between May 2021 and August 2022. Hs-TnI was measured via a bed-side test from whole blood directly in the emergency room, while hs-TnT was measured from plasma through the routine laboratory. Definite ACS was confirmed by coronary angiography. Patients were compared by grouping them into definitive diagnosis of ACS or no ACS. Hs-TnI as well as hs-TnT values were compared for accuracy and predictive values. Routine clinical parameters and comorbidities were documented and compared as well. Agreement between hs-TnI and hs-TnT was assessed by likelihood ratios and Bland Altman plot. Results Overall, 129 patients (65.1% male, 61.8 ± 15.6 years) with acute chest pain were analysed. Median hs-TnI was 7.0 ng/L (IQR: 2.7-15.8), while median hs-TnT was 14 ng/L (IQR: 7.0-31.0). Results for TnI were available faster (average: 1:14 h ± 0:54) compared to TnT. Coronary angiography confirmed ACS in 17 patients (13.2%) displaying significant coronary stenoses requiring intervention. The relative risk of ACS patients to have an elevated hs-TnI result was 6.59 compared to that of 2.29 for the hs-TnT test, meaning that a positive hs-TnI test was a better classifier for validated ACS than that of hs-TnT. Hs-TnI exhibited equivalent negative predictive value to hs-TnT (99%) for definite ACS diagnosis, but had comparatively higher positive predictive value (50.0 vs. 25.8%). Bland Altman plot of hs-TnI versus hs-TnT showed an average difference of -4.6 ng/L (95% CI: -12.4 to 3.2) between the tests. In 39 patients with chronic kidney disease (minimum stage 3a CKD) median hs-TnT (27.0 ng/L, IQR: 16.0-55.0) values were higher than hs-TnI (11.2 ng/L, IQR: 7.5-30.7). Conclusion Bed-side hs-TnI is comparable to hs-TnT with a high degree of agreement. Measurement of troponin I using the rapid bed-side hs-TnI assay possesses a shorter blood-draw-to-result-time than routine troponin T measurement.

The use of a point of care high sensitivity troponin in the investigation of patients presenting to the Emergency Department with undifferentiated chest pain

Abstract Background In 2012 in a hospital, New Zealand, a chest pain pathway was instituted for the use in patients presenting to the Emergency Department (ED) with undifferentiated chest pain. This reduced hospital admissions and ED length of stay (LOS) without adversely affecting outcomes. The pathway consists of risk stratification combined with ECG and troponin testing. The pathway suggests, but does not enforce, that low risk patients can be discharged after a single troponin, intermediate risk patients are for serial troponins (which can be done in ED or the next day in the community), with further testing if appropriate, and high risk patients are reviewed by Cardiology or General medicine. In August 2023, Siemens point of care high sensitivity troponin I (POC-hsTnI) was introduced for the use in ED, although Beckman laboratory troponin I (Lab–hsTnI) is still available. A POC test reduces result turnaround times but until recently there has been a lack of POC assays fulfilling criteria for "high sensitivity". Purpose To ascertain whether the availability of a POC-hsTnI in the ED is a viable option for use in the chest pain pathway Methods A 1 month "snap shot" of all consecutive patients presenting to the ED with chest pain was undertaken and the patients followed for adverse events using electronic notes review. October 2023 was selected for the post POC-hsTnI period and compared with April 2022. Results There were 688 patients presenting to ED with undifferentiated chest pain during October 2023 with a type 1 acute myocardial infarction (AMI) rate of 80 (11.6%), median age 58 (41-72), female 335 (48.7%). POC-hsTnI was used in isolation in 377 (54.8%), in conjunction with Lab-hsTnI in 218 (31.7%) and Lab-hsTnI was used alone in 93 (13.5%). The median turnaround time for POC-hsTnI was 11 minutes (10-11) compared with Lab-hsTnI 87 minutes (61-129). The POC-hsTnI was less sensitive for AMI than the Lab-hsTnI on presentation using the upper reference limit, 72.1% (60.6-81.6) versus 91.5% (83.0-96.4). However, when used with risk stratification, there were no excess adverse events (cardiac death or AMI) at 4 months in patients discharged with a diagnosis of non-cardiac chest pain – 7 (1.4%) (n=495) versus 5 (1.2%), (n=424) in 2022. Median LOS in the ED was 4.4 hours (2.9-6.2) versus 4.0h (3.0-5.9) in 2022. However, a higher proportion of patients had a second cTn: 414 (60.2%) versus 309 (48.4%) and a lower proportion had their second troponin the next day in the community, 28 (6.7%) versus 56 (18.1%). Conclusion The use of a POC-hsTnI is a practical solution to reduce turnaround times for troponin results and has the potential to reduce LOS or allow serial troponins to be measured in a timely manner during their ED visit, obviating the need for a next day community troponin. Whilst POC-hsTnI has a lower early sensitivity for AMI, the use of POC-hsTnI as part of a pathway does not adversely affect outcomes.

Use of point-of-care tests in pharyngotonsillitis – a registry-based study in primary health care

Background Point-of-care (POC) tests, including C-reactive protein (CRP) tests and rapid antigen detection tests (RADT) for group A streptococci (GAS), are widely used in Swedish primary health care (PHC). This study quantifies their use in pharyngotonsillitis and explore their association with antibiotic prescribing. Material and methods Retrospective data from 2012–2016 in Region Kronoberg, Sweden, included all PHC visits with a pharyngotonsillitis diagnosis. Patient characteristics, test usage and antibiotic prescriptions were linked by visit date and personal identification number. Descriptive statistics were used for POC test analysis. Logistic regression assessed the association between CRP levels and antibiotic prescribing. Results Of 24,237 visits, 68% included RADT and 36% included a CRP test, with 89% of CRP tests performed alongside RADT. CRP testing was more frequent in patients with negative (56%) than positive RADTs (42%) (p < .001). Overall, 66% of RADTs were positive. Median CRP levels were 23 mg/l for positive RADT and 31 mg/l for negative RADT (p < .001). Antibiotics were prescribed for 95% of positive RADTs and 43% of negative RADTs (p < .001). In patients with negative RADTs, CRP testing was associated with higher antibiotic prescribing (57%) compared to no CRP testing (26%) (p < .001). Among these patients, CRP levels were associated with prescribing (aOR 1.032; 95% CI 1.029–1.035; p < .001), with 50% of prescriptions occuring at CRP levels ≤ 20 mg/l. Conclusion The use of RADTs and the proportion of positive test were higher than expected, indicating inappropriate use and diagnostic bias. CRP testing, contrary to guidelines, was common and associated with increased antibiotic prescribing.

FRET-Based Dual-Color Carbon Dot Ratiometric Fluorescent Sensor Enables the Smartphone-Integrated Device for Noninvasive and Portable Diagnosis of Chronic Kidney Disease.

Cystatin C (Cys C), a crucial renal disease marker for chronic kidney disease (CKD), plays a vital role in early diagnosis and treatment guidance. However, most current methods for detecting Cys C rely on a single signal and find it difficult to perform noninvasive and portable diagnosis. Here, we developed a ratiometric fluorescent carbon dot (CD) detection system for point-of-care testing (POCT) of Cys C through fluorescence resonance energy transfer (FRET). The detection is based on the hydrolysis effect of papain on a bovine serum albumin (BSA) scaffold and the specific inhibitory effect of Cys C on papain, endowing high-resolution color variance. Moreover, a low-cost, portable, yet reliable smartphone-assisted miniaturized device for real-time quantitative POCT of Cys C has been developed with a limit of detection (LOD) as low as 0.4 μg/mL. This sensing platform can effectively differentiate patients from healthy volunteers, which facilitates self-screening for healthy individuals and home monitoring for CKD patients.

Point-of-care breath sample analysis by semiconductor-based E-Nose technology discriminates non-infected subjects from SARS-CoV-2 pneumonia patients: a multi-analyst experiment.

Metal oxide sensor-based electronic nose (E-Nose) technology provides an easy to use method for breath analysis by detection of volatile organic compound (VOC)-induced changes of electrical conductivity. Resulting signal patterns are then analyzed by machine learning (ML) algorithms. This study aimed to establish breath analysis by E-Nose technology as a diagnostic tool for severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pneumonia within a multi-analyst experiment. Breath samples of 126 subjects with (n=63) or withoutSARS-CoV-2 pneumonia (n=63) were collected using the ReCIVA® Breath Sampler, enriched and stored on Tenax sorption tubes, and analyzed using an E-Nose unit with 10 sensors. ML approaches were applied by three independent data analyst teams and included a wide range of classifiers, hyperparameters, training modes, and subsets of training data. Within the multi-analyst experiment, all teams successfully classified individuals as infected or uninfected with an averaged area under the curve (AUC) larger than 90% and misclassification error lower than 19%, and identified the same sensor as most relevant to classification success. This new method using VOC enrichment and E-Nose analysis combined with ML can yield results similar to polymerase chain reaction (PCR) detection and superior to point-of-care (POC) antigen testing. Reducing the sensor set to the most relevant sensor may prove interesting for developing targeted POC testing.

52 The bag is not always bad: Implementing a two-step method for urine testing on the inpatient paediatric units

Abstract Background Urinary tract infections (UTIs) are a common source of infection in children. Best practice for diagnosis includes interpreting a urinalysis (UA) and urine culture. Urine cultures obtained through bladder catheterization are invasive and time consuming. A two-step approach with noninvasive UA screen, followed by urine culture if positive has previously demonstrated a reduction in unnecessary catheterizations and urine cultures in children 6-24 months with suspected UTIs. Pre-intervention, there was inconsistent use of screening point-of-care urinalysis prior to bladder catheterization for culture. Objectives To decrease the number of bladder catheterizations in children 6-24 months with a negative screen on Point of Care Test (POCT) urinalysis by 25% over 1 year on paediatrics wards at a paediatric tertiary care centre. Outcome measures: 1. Proportion of bladder catheterizations with negative or no UA screen prior 2. Proportion of UA completed as POCT rather than lab sample Process measures: 1. Number of urinary catheterizations performed for UTI screen 2. Number of times pathway is followed Balancing measure: 1. Missed UTIs Design/Methods Baseline data was collected from the paediatric inpatient units at a tertiary paediatric hospital from April 2020 – April 2021. A two-step pathway for collecting urine samples was adopted, including POCT UA screen on a bag sample, followed by bladder catheterization for culture if positive. The pathway was implemented using the Model for Improvement and multiple PDSA cycles. Intervention focused on education, interdisciplinary collaboration, and process standardization. Results Baseline data demonstrated a high rate of urinary catheter cultures despite a negative UA or no UA prior (69%). After pathway implementation, this rate decreased to 23%, with a reduction in initial UA collected by catheter from 14% to 5% (figure 1). The number of POCT UA performed has increased from a median of 64% pre-intervention to 80% post-intervention, resulting in fewer samples processed in the lab (figure 2). Conclusion Variability in practice for specimen choice for collection and investigation contributed to unnecessary catheterizations. Process standardization successfully improved patient-centered care and efficiency. Next steps include broadening pathway inclusion criteria to the 3–6-month age group. Potential competing interests This work was partially supported by the UMC (Utilization Management Committee) Resource Stewardship Grant. The authors declare no additional sources of funding or conflicts of interest.

Target-Triggered Ultrafast Chondroitin Gelation Enabled Power-Free and Point-of-Care Bioassays.

Point-of-care (POC) tests increasingly highlight the importance of portable, cost-effective, and visually quantitative detection of biomarkers. Herein, we developed a power-free and visual signal-readout POC sensor based on the target-triggered ultrafast gelation process. In the gelation process, the target triggered the cascade reaction catalyzed by oxidase and ferrous glycinate to produce carbon radicals that immediately initiated the rapid polymerization and cross-linking of acryloylated chondroitin sulfate and dimethylacrylamide. This highly efficient enzymatic polymerization process contributed to the ultrafast generation of chondroitin hydrogel within 1 min at 25 °C. The increase in viscosity of aqueous solution resulted from hydrogel formation was then visually measured according to the distance of solution migration on a tick-labeled pH test strip, which thus realized the quantification of a target. By utilizing glucose oxidase as an oxidase model during the gelation process, this POC sensor was successfully employed in the rapid quantitative detection of glucose without the need for any auxiliary instruments. Benefiting from the specificity and stability of the enzymatic polymerization reaction, the sensor exhibited excellent performance in the detection of glucose in clinical blood samples. Moreover, the sensor was further extended to uric acid detection and enabled accurate assay in clinical urine samples, which indicated the versatility and practicability of this sensor in the POC test.

The potential promise and pitfalls of point-of-care viral load monitoring to expedite HIV treatment decision-making in rural Uganda: a qualitative study

BackgroundHIV treatment programs in Africa have implemented centralized testing for routine viral load monitoring (VLM), which may result in specimen processing delays inhibiting timely return of viral load results. Decentralized, point-of-care (PoC) VLM is a promising tool for expediting HIV clinical decision-making but remains unavailable in most African settings. We qualitatively explored the perceived feasibility and appropriateness of PoC VLM to address gaps along the viral load monitoring continuum in rural Uganda.MethodsBetween May and September 2022, we conducted 15 in-depth interviews with HIV clinicians (facility in-charges, clinical officers, nurses, counselors) and six focus group discussions with 47 peer health workers from three south-central Ugandan districts. Topics explored centralized VLM implementation and opportunities/challenges to optimizing routine VLM implementation with PoC testing platforms. We explored perspectives on PoC VLM suitability and feasibility using iterative thematic analysis. Applying the Framework Method, we then mapped salient constraints and enablers of PoC VLM to constructs from the Consolidated Framework for Implementation Research.ResultsClinicians and peers alike emphasized centralized viral load monitoring’s resource-intensiveness and susceptibility to procedural/infrastructural bottlenecks (e.g., supply stockouts, testing backlogs, community tracing of clients with delayed VLM results), inhibiting timely clinical decision-making. Participants reacted enthusiastically to the prospect of PoC VLM, anticipating accelerated turnarounds in specimen processing, shorter and/or fewer client encounters with treatment services, and streamlined efficiencies in HIV care provision (including expedited VLM-driven clinical decision-making). Anticipated constraints to PoC VLM implementation included human resource requirements for processing large quantities of specimens (especially when machinery require repair), procurement and maintenance costs, training needs in the existing health workforce for operating point-of-care technology, and insufficient space in lower-tier health facilities to accommodate installation of new laboratory equipment.ConclusionsAnticipated implementation challenges, primarily clustering around resource requirements, did not diminish enthusiasm for PoC VLM monitoring among rural Ugandan clinicians and peer health workers, who perceived PoC platforms as potential solutions to existing inefficiencies within the centralized VLM ecosystem. Prioritizing PoC VLM rollout in facilities with available resources for optimal implementation (e.g., adequate physical and fiscal infrastructure, capacity to manage high specimen volumes) could help overcome anticipated barriers to decentralizing viral load monitoring.

Advancing magnetic flow cytometry to quantitative epitope analysis in high hematocrit conditions for point-of-care testing

Quantitative cell function measurements are essential for many clinical decisions but are primarily tied to centralized laboratories. Limited access to these laboratories in low-resource settings or for immobile patients highlights the urgent need for Point-of-Care testing (POCT) infrastructure. Magnetic flow cytometers (MFC) offer a solution, albeit phenotyping is limited, and sample processing steps like cell lysis or washing increase MFC's workflow complexity. Here, we investigate conditions for novel phenotyping and direct cell concentration quantification in a streamlined workflow suitable for POCT in high hematocrit environments. We characterize magnetic nanoparticles (MNP) by their size, magnetic moment, and opportunities for high signal-to-noise ratios. With adapted theoretical models, we provide the framework for quantifying bound MNPs per cell. This reveals labeling quality and gives insight into system requirements for reliable cell detection and rational cell phenotyping. We investigate temporal labeling dynamics, which show suboptimal MNP binding kinetics in whole blood (WB), leading to long incubation periods and only 50% recovery concentrations. With our streamlined workflow favoring small (<50 nm) MNPs, we quantify CD14+ monocytes in WB and achieve coefficients of variation of <11%. By simultaneously assessing quantitative epitope expression, we extend MFC's capabilities to clinical subtyping for POCT.

Enhanced bipolar electrode electrochemiluminescence biosensor for ultrasensitive monitoring of alkaline phosphatase activity during osteoblast differentiation by integrating electrocatalytic and enzymatic strategies

Alkaline phosphatase (ALP) is an important biomarker that reflects osteoblast activity and bone growth. Accurately detecting ALP activity is of pivotal clinical significance for the diagnosis and differentiation of bone system diseases. In this work, an enhanced bipolar electrode electrochemiluminescence (BPE-ECL) biosensor based on enzyme catalysis and electrocatalysis was proposed for ultrasensitive detection of ALP in osteoblasts. Carbon nitride nanosheets (CNNS) were utilized as electrocatalysts to facilitate the electrochemical reaction of bipyridine ruthenium (Ru(bpy)32+) and tripropylamine (TPrA) in the reporting cell. Meanwhile, in the sensing cell, the target ALP catalyzed the conversion of p-aminophenyl phosphate monohydrate into p-aminophenol (p-AP). The p-AP was subsequently oxidized at the anode of the driving electrode, producing electrons and increasing the Faradaic current of BPE. The dual-signal amplification strategy, combining electrocatalysis and enzyme catalysis, resulted in a 10-fold enhancement of the ECL intensity of Ru(bpy)32+/TPrA. The BPE-ECL biosensor achieved ultrasensitive detection of ALP with a detection limit as low as 1.9×10−6 U/L, and was successfully applied to monitor ALP activity in osteoblast cells. Additionally, a portable smartphone imaging was developed for the visual detection of ALP. This research introduces an innovative BPE-ECL biosensor for the monitoring of ALP activity and point-of-care testing (POCT) in osteoblasts in clinical settings.

Current status of schistosomiasis in school-aged children in Mwanga district, Tanzania: impact of two decades of annual Mass Drug Administration programme.

Schistosomiasis is a neglected tropical disease with significant health implications, particularly among children. A cross-sectional study was conducted among school-aged children (SAC) in Mwanga district, Tanzania, a region known to be co-endemic for S. haematobium and S. mansoni infection and where annual mass drug administration (MDA) has been conducted for 20 years. In total, 576 SAC from 5 schools provided a urine sample for the detection of Schistosoma circulating anodic antigen using the upconverting particle-based lateral flow (UCP-LF CAA) test. Additionally, the potential of the point-of-care circulating cathodic antigen (POC-CCA) and microhaematuria dipstick test as field-applicable diagnostic alternatives for schistosomiasis were assessed and the prevalence outcome compared to UCP-LF CAA. Risk factors associated with schistosomiasis was assessed based on UCP-LF CAA. The UCP-LF CAA test revealed an overall schistosomiasis prevalence of 20.3%, compared to 65.3% based on a combination of POC-CCA and microhaematuria dipstick. No agreement was observed between the combined POC tests and UCP-LF CAA. Factors associated with schistosomiasis included age (5–10 years), involvement in fishing, farming, swimming activities and attending 2 of the 5 primary schools. Our findings suggest a significant progress in infection control in Mwanga district due to annual MDA, although not enough to interrupt transmission. Accurate diagnostics play a crucial role in monitoring intervention measures to effectively combat schistosomiasis.

Evaluation of a Commercial Rapid Molecular Point-of-Care Assay for Differential Diagnosis Between SARS-CoV-2 and Flu A/B Infections in a Pediatric Setting.

Given the ongoing COVID-19 pandemic, there is a need to identify SARS-CoV-2 and to differentiate it from other respiratory viral infections, especially influenza A and B, in various critical settings. Since their introduction, the use of rapid antigen tests has spread worldwide, but there is variability in their diagnostic accuracy. In the present study, we evaluated the clinical performance of the ID NOW™ COVID-19 2.0, a molecular point-of-care test (POCT) based on enzymatic isothermal amplification for the differential diagnosis of SARS-CoV-2 and influenza A/B in a pediatric emergency setting. A cohort of pediatric patients admitted between December 2022 and February 2023 were simultaneously tested with the POCT and standard laboratory molecular assay. Our findings showed high negative agreement of the POCT assay across the different age groups for SARS-CoV-2, influenza A, and influenza B (more than 98.0%), while its positive agreement varied significantly for the abovementioned viral species from 50.0% to 100%. These results highlight the potential of the ID NOW™ COVID-19 2.0 POCT assay as a reliable and rapid tool for excluding SARS-CoV-2 and influenza A/B infections in symptomatic pediatric patients, although its variable positive agreement suggests a need for confirmatory RT-qPCR testing in certain clinical and epidemiological settings in order to ensure accurate diagnosis and appropriate patient management.

Flower-Shaped PCR Scaffold-Based Lateral Flow Bioassay for Bacillus cereus Endospores Detection

Bacillus cereus, a foodborne pathogen, produces resilient endospores that are challenging to detect with conventional methods. This study presents a novel Flower-Shaped PCR Scaffold-based Lateral Flow Biosensor (FSPCRS-LFB), which employs an aptamer-integrated PCR scaffold as capture probes, replacing the traditional streptavidin-biotin (SA-Bio) approach. The FSPCRS-LFB demonstrates high sensitivity and cost-efficiency in detecting B. cereus endospores, with a limit of detection (LOD) of 4.57 endospores/mL a visual LOD of 102 endospores/mL, and a LOD of 6.78 CFU/mL for endospore-cell mixtures. In chicken and tea samples, the platform achieved LODs of 74.5 and 52.8 endospores/mL, respectively, with recovery rates of 82.19% to 97.88%. Compared to existing methods, the FSPCRS-LFB offers a 3.7-fold increase in sensitivity while reducing costs by 26% over the SA-Bio strategy and 87.5% over rolling circle amplification (RCA). This biosensor provides a rapid, sensitive and cost-effective solution for point-of-care testing (POCT) of B. cereus endospores, expanding detection capabilities and offering novel approaches for pathogen detection.