A Paper-Based Multiplexed Transaminase Test for Low-Cost, Point-of-Care Liver Function Testing

In developed nations, monitoring for drug-induced liver injury through serial measurements of serum transaminases [aspartate aminotransferase (AST) and alanine aminotransferase (ALT)] in at-risk individuals is the standard of care. Despite the need, monitoring for drug-related hepatotoxicity in resource-limited settings is often limited by expense and logistics, even for patients at highest risk. This article describes the development and clinical testing of a paper-based, multiplexed microfluidic assay designed for rapid, semiquantitative measurement of AST and ALT in a fingerstick specimen. Using 223 clinical specimens obtained by venipuncture and 10 fingerstick specimens from healthy volunteers, we have shown that our assay can, in 15 min, provide visual measurements of AST and ALT in whole blood or serum, which allow the user to place those values into one of three readout “bins” [5× ULN, corresponding to tuberculosis/HIV treatment guidelines] with >90% accuracy. These data suggest that the ultimate point-of-care fingerstick device will have high impact on patient care in low-resource settings.Chemistry and Chemical Biolog

From the Bench to the Field in Low-Cost Diagnostics: Two Case Studies

Despite the growth of research in universities on point-of-care (POC) diagnostics for global health, most devices never leave the laboratory. The processes that move diagnostic technology from the laboratory to the field—the processes intended to evaluate operation and performance under realistic conditions—are more complicated than they might seem. Two case studies illustrate this process: the development of a paper-based device to measure liver function, and the development of a device to identify sickle cell disease based on aqueous multiphase systems (AMPS) and differences in the densities of normal and sickled cells. Details of developing these devices provide strategies for forming partnerships, prototyping devices, designing studies, and evaluating POC diagnostics. Technical and procedural lessons drawn from these experiences may be useful to those designing diagnostic tests for developing countries, and more generally, technologies for use in resource-limited environments.Chemistry and Chemical Biolog

Molecular diagnostic platforms for point-of-need pathogen detection

2021 Summer.Includes bibliographical references.Rapid, accurate, reliable nucleic acid testing (NAT) platforms are essential in the diagnosis and management of diseases. The inherent complexity associated with NAT requires that such testing be performed in centralized laboratories by highly trained personnel. Modified molecular technologies that can be used at the point-of-care (POC) are needed to improve the turnaround times of results and lower the global burden of infectious diseases. To help address this urgent need, we have developed a nucleic acid sensor platform utilizing nuclease protection and lateral flow detection for rapid, point-of-need nucleic acid analysis. We have also improved the analytical performance of the assay by pairing it with isothermal padlock rolling circle amplification (RCA). RCA is one of the simplest and most versatile isothermal amplification techniques as it only requires one primer and a strand-displacing polymerase. Utilizing our rolling circle amplification lateral flow platform, we have developed assays for beta-lactamase resistance genes for antimicrobial resistance monitoring and severe acute respiratory virus coronavirus 2 (SARS-CoV-2). We have also explored the use of exponential isothermal amplification to further improve the assay limit of detection. We also propose a microfluidic device to rapidly detect the RCA amplicons. The device allows programmable sequential delivery of reagents to a detection region, reducing the number of user steps. With further development, such microfluidic devices can be used to develop fully integrated sample-to-result molecular diagnostic platforms that integrate sample pretreatment, amplification, and detection in an easy-to-use, point-of-need nucleic acid sensor platform. Chapter 1 presents a brief review of the nucleic acid testing landscape, the challenges associated with the development of point-of-need nucleic acid sensors and recent successes utilizing paper-based devices for fully integrated sample-to-result sensors. Chapters 2 and 3 discuss the development of the nuclease protection lateral flow assay and padlock probe-based rolling circle amplification lateral flow assay. Chapter 4 describes our work on the use of exponential RCA to improve the limit of detection of the SARS-CoV-2 assay. In Chapter 5, we present our work on a paper-plastic microfluidic device for the rapid detection of the RCA amplicon. We believe that such devices can be used for the development of integrated molecular diagnostic sensor platforms that can be used at the point-of-need in resource-limited settings

Preventive Maintain of Ventilators and its Cost Consideration

Background Maintenance is the core function of biomedical engineering and is essential for the optimum functioning of equipment This study was undertaken to understand the current maintenance practices of ventilator and its cost implications from administrative point of view Methodology 179 Ventilators supplied and installed by one vendor in different wards of the hospital were studied It was a retrospective descriptive study Equipment related data was taken from various service reports This data was used to calculate spares failure and their costs implication Results A total of 692 maintenance visits were undertaken for 179 ventilators of 5 different modals over 27 months by 6 Bio- Medical Engineers BME The mean number of spare changed throughout the study was 2 73 The uptime was within satisfactory limits The yearly repair to cost ratio was 3 50 The cost of spare changed was a factor of modal under consideration and the status of equipment concerning its coverage under maintenance contact Conclusion The findings of the study should enable researchers in the future to formulate an effective equipment maintenance policy for the hospita

Seasonal variations in respiratory morbidity in primary care and its correlation with the quality of air in urban Odisha, India.

Poor air quality, especially in urban regions among low-and middle-income countries such as India poses a significant healthcare challenge. Amongst urban areas, metropolitan cities garner the utmost importance for air quality related policies and studies with limited studies from tier II cities which are thought to be relatively immune to air pollution. Hence, we aimed to identify the most frequent respiratory morbidities and explore its correlation with exposure to ambient PM2.5 particles in Bhubaneswar (a tier II city in coastal India), Odisha. A chart review was carried out through data extracted from the records of urban health centres. Data on PM2.5 concentrations were obtained from Odisha State Pollution Control Board. The morbidities were coded by using the International Classification of Primary Care‑2 system (ICPC-2). Descriptive statistics such as incidence of respiratory illnesses was computed across seasons. The ecological correlation between respiratory morbidity patterns and corresponding concentration of PM2.5 in air was analysed for each season. A positive correlation (r = o.94) between PM2.5 and respiratory morbidities was observed. The incidence of respiratory morbidities was 183.31 per 1000 person year. We identified 21 out of 43 respiratory diseases classified under ICPC-2. Upper Respiratory Tract Infection was the most commonly (116.8 per 1000 person year) incident condition. We observed one-fourth increase in the incidence of respiratory illnesses during winters. Respiratory morbidities are common in urban Bhubaneswar which follows a seasonal pattern and are possibly linked with the seasonal variations in levels of PM2.5 particles. Our study highlights that tier II cities are equally prone to health effects of air pollution. Future programmes and policies should take these cities into consideration too

Rapid light transmittance measurements in paper-based microfluidic devices

We developed methodology and built a portable reader to assess light transmittance in paper-based microfluidic devices in a highly sensitive, user-friendly and field-appropriate manner. By sandwiching the paper assay between micro-light-emitting diodes and micro-photodetectors, the reader quantifies light transmittance through the paper independent of ambient light conditions. To demonstrate the utility of the reader, we created a single-use paper-based microfluidic assay for measurement of alanine aminotransferase, an indicator of liver health in blood. The paper assay and reader system accurately differentiated alanine aminotransferase levels across the human reference range and demonstrated significant differences at clinically relevant cutoff values. Results were provided within 10 min and were automatically generated without complex image analysis. Performance of this point-of-care diagnostic rivals the accuracy of lab-based spectrometer tests at a fraction of the cost, while matching the timeliness of low-cost portable assays, which have historically shown lower accuracy. This combination of features allows flexible deployment of low cost and quantitative diagnostics to resource-poor settings. Keywords: Paper microfluidics, Colorimetric, Light transmission, Alanine aminotransferase, Enzymatic reactions, Continuous monitorin

Antimicrobial resistance in food-borne pathogens at the human-animal interface: Results from a large surveillance study in India

Background: The burden of foodborne diseases and antimicrobial resistance carried by key foodborne pathogens in India is unknown due to a lack of an integrated surveillance system at the human-animal interface. Methods: We present data from the WHO-AGISAR (Advisory Group on Integrated Surveillance of Antimicrobial Resistance), India project. Concurrent human and animal sampling was done across a large area across north India. Community-acquired diarrhea cases (n = 1968) of all age groups were included. Cross-sectional sampling of stool/ intestinal contents (n = 487) and meat samples (n = 419) from food-producing animals was done at farms, retail shops, and slaughterhouses. Pathogens were cultured and identified, and antimicrobial susceptibility was performed. Results: Over 80% of diarrhoeal samples were obtained from moderate to severe diarrhea patients, which yielded EAEC (5%), ETEC (4.84%), EPEC (4.32%), and Campylobacter spp. (2%). A high carriage of EPEC (32.11%) and Campylobacter spp. (24.72%) was noted in food animals, but the prevalence of ETEC (2%) and EAEC (1%) was low. Atypical EPEC (aEPEC, 84.52%, p ≤0.0001) were predominant and caused milder diarrhea. All EPEC from animal/poultry were aEPEC. Overall, a very high level of resistance was observed, and the MDR rate ranged from 29.2% in Campylobacter spp., 53.6% in EPEC, and 59.8% in ETEC. Resistance to piperacillin-tazobactam, cefepime, ceftriaxone, and co-trimoxazole was significantly higher in human strains. In contrast, resistance to ciprofloxacin, aminoglycosides, and tetracycline was higher in animal strains, reflecting the corresponding usage in human and animal sectors. ESBL production was commoner in animal isolates than in humans, indicating high use of third-generation cephalosporins in the animal sector. C. hyointestinalis is an emerging zoonotic pathogen, first time reported from India. Conclusion: In one of the most extensive studies from India, a high burden of key foodborne pathogens with MDR and ESBL phenotypes was found in livestock, poultry, and retail meat

Performance of an Optimized Paper-Based Test for Rapid Visual Measurement of Alanine Aminotransferase (ALT) in Fingerstick and Venipuncture Samples.

A paper-based, multiplexed, microfluidic assay has been developed to visually measure alanine aminotransferase (ALT) in a fingerstick sample, generating rapid, semi-quantitative results. Prior studies indicated a need for improved accuracy; the device was subsequently optimized using an FDA-approved automated platform (Abaxis Piccolo Xpress) as a comparator. Here, we evaluated the performance of the optimized paper test for measurement of ALT in fingerstick blood and serum, as compared to Abaxis and Roche/Hitachi platforms. To evaluate feasibility of remote results interpretation, we also compared reading cell phone camera images of completed tests to reading the device in real time.96 ambulatory patients with varied baseline ALT concentration underwent fingerstick testing using the paper device; cell phone images of completed devices were taken and texted to a blinded off-site reader. Venipuncture serum was obtained from 93/96 participants for routine clinical testing (Roche/Hitachi); subsequently, 88/93 serum samples were captured and applied to paper and Abaxis platforms. Paper test and reference standard results were compared by Bland-Altman analysis.For serum, there was excellent agreement between paper test and Abaxis results, with negligible bias (+4.5 U/L). Abaxis results were systematically 8.6% lower than Roche/Hitachi results. ALT values in fingerstick samples tested on paper were systematically lower than values in paired serum tested on paper (bias -23.6 U/L) or Abaxis (bias -18.4 U/L); a correction factor was developed for the paper device to match fingerstick blood to serum. Visual reads of cell phone images closely matched reads made in real time (bias +5.5 U/L).The paper ALT test is highly accurate for serum testing, matching the reference method against which it was optimized better than the reference methods matched each other. A systematic difference exists between ALT values in fingerstick and paired serum samples, and can be addressed by application of a correction factor to fingerstick values. Remote reading of this device is feasible

Bias values and associated 95% confidence intervals (CI) for Bland-Altman comparisons shown in Fig 3A–3D.

<p>n/a, not applicable.</p><p>Bias values and associated 95% confidence intervals (CI) for Bland-Altman comparisons shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0128118#pone.0128118.g003" target="_blank">Fig 3A–3D</a>.</p