scholarly journals Development and Large-Scale Validation of A Highly Accurate SARS-COV-2 Serological Test Using Regular Test Strips for Autonomous and Affordable Finger-Prick Sample Collection, Transportation, and Storage

2021 ◽  
Author(s):  
Renata G.F. Alvim ◽  
Tulio M. Lima ◽  
Danielle A. S. Rodrigues ◽  
Federico F. Marsili ◽  
Vicente B. T. Bozza ◽  
...  
Keyword(s):  
Low Income ◽  
Large Scale ◽  
Serological Test ◽  
Low Cost ◽  
Venous Blood ◽  
Hek293 Cells ◽  
Epidemiological Surveillance ◽  
Sample Collection ◽  
S Protein ◽  
Finger Prick

Abstract Accurate serological tests are essential tools to allow adequate monitoring and control of COVID-19 spread. Production of a low-cost and high-quality recombinant viral antigen can enable the development of reliable and affordable serological assays, which are urgently needed to facilitate epidemiological surveillance studies in low-income economies. Trimeric SARS-COV-2 spike (S) protein was produced in serum-free, suspension-adapted HEK293 cells. Highly purified S protein was used to develop an ELISA, named S-UFRJ test. It was standardized to work with different types of samples: (i) plasma or serum from venous blood samples; (ii) eluates from dried blood spots (DBS) obtained by collecting blood drops from a finger prick. We developed a cost-effective, scalable technology to produce S protein based on its stable expression in HEK293 cells. Using this recombinant antigen, we presented a workflow for test development in the setting of a pandemic, starting from limited amounts of samples up to reaching final validation with hundreds of samples. Test specificity was determined to be 98.6%, whereas sensitivity was 95% for samples collected 11 or more days after symptoms onset. A ROC analysis allowed optimizing the cut-off and confirming the high accuracy of the test. Endpoint titers were shown to correlate with virus neutralization assessed as PRNT90. There was excellent agreement between plasma and DBS samples, significantly simplifying sample collection, storing, and shipping. An overall cost estimate revealed that the final retail price could be in the range of one US dollar. The S-UFRJ assay developed herein meets the quality requirements of high sensitivity and specificity. The low cost and the use of mailable DBS samples allow for serological surveillance and follow-up of SARS-CoV-2 vaccination of populations regardless of geographical and socio-economic aspects. We hope the detailed guidelines for the development of an affordable and accurate anti-spike SARS-COV-2 ELISA, such as S-UFRJ described here, will stimulate governmental and non-governmental health agencies in other countries to engage in much-needed large-scale studies monitoring the spread and immunity to SARS-COV-2 infection.

scholarly journals An affordable anti-SARS-COV-2 spike protein ELISA test for early detection of IgG seroconversion suited for large-scale surveillance studies in low-income countries

2020 ◽  
Author(s):  
Renata G. F. Alvim ◽  
Tulio M. Lima ◽  
Danielle A. S. Rodrigues ◽  
Federico F. Marsili ◽  
Vicente B. T. Bozza ◽  
...  
Keyword(s):  
Low Income ◽  
Large Scale ◽  
Low Cost ◽  
Venous Blood ◽  
Hek293 Cells ◽  
Epidemiological Surveillance ◽  
Low Income Countries ◽  
Serological Tests ◽  
S Protein ◽  
Surveillance Studies

AbstractBackgroundAccurate serological tests are essential tools to allow adequate monitoring and control of COVID-19 spread. Production of a low-cost and high-quality recombinant viral antigen can enable the development of reliable and affordable serological assays, which are urgently needed to facilitate epidemiological surveillance studies in low-income economies.MethodsTrimeric SARS-COV-2 spike (S) protein was produced in serum-free, suspension-adapted HEK293 cells. Highly purified S protein was used to develop an ELISA, named S-UFRJ test. It was standardized to work with different types of samples: (i) plasma or serum from venous blood samples; (ii) eluates from dried blood spots (DBS) obtained by collecting blood drops from finger prick.FindingsWe developed a cost-effective, scalable technology to produce S protein based on its stable expression in HEK293 cells. Using this recombinant antigen we presented a workflow for test development in the setting of a pandemic, starting from limited amounts of samples up to reaching final validation with hundreds of samples. Test specificity was determined to be 98.6%, whereas sensitivity was 95% for samples collected 11 or more days after symptoms onset. A ROC analysis allowed optimizing the cut-off and confirming the high accuracy of the test. Endpoint titers were shown to correlate with virus neutralization assessed as PRNT90. There was excellent agreement between plasma and DBS samples, significantly simplifying sample collection, storing and shipping. An overall cost estimate revealed that final retail price could be in the range of one US dollar.InterpretationThe S-UFRJ assay developed herein meets the quality requirements of high sensitivity and specificity. The low cost and the use of mailable DBS samples allow for serological surveillance of populations regardless of geographical and socio-economic aspects, with special relevance for public health policy actions in low-income countries.FundingCTG, Senai DN/CETIQT, FAPERJ, CNPq, CAPES and Instituto Serrapilheira.

scholarly journals Evaluation of a Low-Cost Commercial Actigraph and Its Potential Use in Detecting Cultural Variations in Physical Activity and Sleep

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3774
Author(s):  
Pavlos Topalidis ◽  
Cristina Florea ◽  
Esther-Sevil Eigl ◽  
Anton Kurapov ◽  
Carlos Alberto Beltran Leon ◽  
...  
Keyword(s):  
Physical Activity ◽  
Low Income ◽  
Large Scale ◽  
Low Cost ◽  
Low Income Countries ◽  
Time Data ◽  
Cultural Variations ◽  
Step Counts ◽  
Scale Step ◽  
Potential Use

The purpose of the present study was to evaluate the performance of a low-cost commercial smartwatch, the Xiaomi Mi Band (MB), in extracting physical activity and sleep-related measures and show its potential use in addressing questions that require large-scale real-time data and/or intercultural data including low-income countries. We evaluated physical activity and sleep-related measures and discussed the potential application of such devices for large-scale step and sleep data acquisition. To that end, we conducted two separate studies. In Study 1, we evaluated the performance of MB by comparing it to the GT3X (ActiGraph, wGT3X-BT), a scientific actigraph used in research, as well as subjective sleep reports. In Study 2, we distributed the MB across four countries (Austria, Germany, Cuba, and Ukraine) and investigated physical activity and sleep among these countries. The results of Study 1 indicated that MB step counts correlated highly with the scientific GT3X device, but did display biases. In addition, the MB-derived wake-up and total-sleep-times showed high agreement with subjective reports, but partly deviated from GT3X predictions. Study 2 revealed similar MB step counts across countries, but significant later wake-up and bedtimes for Ukraine than the other countries. We hope that our studies will stimulate future large-scale sensor-based physical activity and sleep research studies, including various cultures.

scholarly journals Comparison of Dried Blood Spots and Venous Blood for the Detection of SARS-CoV-2 Antibodies in a Population of Nursing Home Residents

2021 ◽  
Author(s):  
Eline Meyers ◽  
Stefan Heytens ◽  
Asangwing Formukong ◽  
Hanne Vercruysse ◽  
An De Sutter ◽  
...  
Keyword(s):  
Nursing Home ◽  
General Population ◽  
Large Scale ◽  
Room Temperature ◽  
Venous Blood ◽  
Nursing Home Residents ◽  
Dried Blood Spots ◽  
Serological Tests ◽  
Finger Prick ◽  
Study Population

Since the implementation of newly developed SARS-CoV-2 vaccines in the general population, serological tests are of increasing importance. Because DBS samples can be obtained with a finger prick and can be shipped and stored at room temperature, they are optimal for use in large-scale SARS-CoV-2 serosurveillance or postauthorization vaccination studies, even in an elderly study population.

scholarly journals A serological assay to detect SARS-CoV-2 antibodies in at-home collected finger-prick dried blood spots

2020 ◽  
Author(s):  
Donna Grace Karp ◽  
Kenneth Danh ◽  
David Seftel ◽  
Peter Robinson ◽  
Cheng-ting Tsai
Keyword(s):  
Healthcare Worker ◽  
Large Scale ◽  
Health Care Systems ◽  
Dried Blood Spots ◽  
Sample Collection ◽  
Finger Prick ◽  
Care Systems ◽  
Hard To Reach Populations ◽  
Development And Validation ◽  
At Home

Accurate surveillance of coronavirus disease 2019 (COVID-19) incidence requires large-scale testing of the population. Current testing methods require in-person collection of biospecimens by a healthcare worker, limiting access of individuals who do not have access to testing facilities while placing both the patient and healthcare worker at risk of exposure to infection. We report the development and validation of a at-home finger-prick dried blood spot collection kit and an analysis method. We demonstrated 100% sensitivity and specificity using at-home collected specimens across the US. Such methods may facilitate the conduct of unbiased serosurveys within hard to reach populations and help reduce the sample collection burden of serological testing on both health care systems and individuals alike.

scholarly journals Performance characteristics of an instrument-free point-of-care CD4 test (VISITECT®CD4) for use in resource-limited settings

2020 ◽  
Vol 48 (9) ◽  
pp. 030006052095502
Author(s):  
Vairamohan Vidhyavathi ◽  
Hussain Syed Iqbal ◽  
Kannaiyan Kanthamani ◽  
Sunil Suhas Solomon ◽  
Paneerselvam Nandagopal ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Predictive Value ◽  
Point Of Care ◽  
Low Cost ◽  
Venous Blood ◽  
Hiv Positive ◽  
Resource Limited ◽  
Immunodeficiency Virus ◽  
Finger Prick ◽  
Sensitivity Specificity

Objective CD4+ T lymphocyte count remains the most common biomarker of immune status and disease progression in human immunodeficiency virus (HIV)-positive individuals. VISITECT®CD4 is an instrument-free, low-cost point-of-care CD4 test with a cut-off of 350 CD4 cells/μL. This study aimed to evaluate VISITECT®CD4 test's diagnostic accuracy. Methods Two hundred HIV-positive patients attending a tertiary HIV centre in South India were recruited. Patients provided venous blood for reference and VISITECT®CD4 tests. An additional finger-prick blood sample was obtained for VISITECT®CD4. VISITECT®CD4's diagnostic performance in identifying individuals with CD4 counts ≤350 cells/μL was assessed by calculating sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) taking flow cytometry as the reference. Results The overall agreement between VISITECT®CD4 and flow cytometry was 89.5% using venous blood and 81.5% using finger-prick blood. VISITECT®CD4 showed better performance using venous blood [sensitivity: 96.6% (95% confidence interval: 92.1%–98.9%), specificity: 70.9% (57.1%–82.4%), PPV: 89.7% (83.9%–94.0%) and NPV: 88.6% (75.4%–96.2%)] than using finger-prick blood [sensitivity: 84.8% (77.9%–90.2%), specificity: 72.7% (59.0%–83.9%), PPV: 89.1% (82.7%–93.8%) and NPV: 64.5% (51.3%–76.3%)]. Conclusion VISITECT®CD4 performed well using venous blood, demonstrating its potential utility in decentralization of CD4 testing services in resource-constrained settings.

scholarly journals Field Performance and Diagnostic Accuracy of a Low-Cost Instrument-Free Point-of-Care CD4 Test (Visitect CD4) Performed by Different Health Worker Cadres among Pregnant Women

2018 ◽  
Vol 57 (2) ◽  
Author(s):  
Stanley Luchters ◽  
Karl Technau ◽  
Yasmin Mohamed ◽  
Matthew F. Chersich ◽  
Paul A. Agius ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Pregnant Women ◽  
Health Worker ◽  
Rural Areas ◽  
Point Of Care ◽  
Low Cost ◽  
Venous Blood ◽  
Field Performance ◽  
Hiv Care ◽  
Finger Prick

ABSTRACT Measuring CD4 counts remains an important component of HIV care. The Visitect CD4 is the first instrument-free low-cost point-of-care CD4 test with results interpreted visually after 40 min, providing a result of ≥350 CD4 cells/mm3. The field performance and diagnostic accuracy of the test was assessed among HIV-infected pregnant women in South Africa. A nurse performed testing at the point-of-care using both venous and finger-prick blood, and a counselor and laboratory staff tested venous blood in the clinic laboratory (four Visitect CD4 tests/participant). Performance was compared to the mean CD4 count from duplicate flow cytometry tests on venous blood (FACSCalibur Trucount). In 2017, 156 patients were enrolled, providing a total of 624 Visitect CD4 tests (468 venous and 156 finger-prick samples). Of 624 tests, 28 (4.5%) were inconclusive. Generalized linear mixed modeling showed better performance of the test on venous blood (sensitivity = 81.7%; 95% confidence interval [CI] = 72.3 to 91.1]; specificity = 82.6%, 95% CI = 77.1 to 88.1) than on finger-prick specimens (sensitivity = 60.7%; 95% CI = 45.0 to 76.3; specificity = 89.5%, 95% CI = 83.2 to 95.8; P = 0.001). No difference in performance was detected by cadre of health worker (P = 0.113) or between point-of-care versus laboratory-based testing (P = 0.108). Adequate performance of Visitect CD4 with different operators and at the point of care, with no need of electricity or instrument, shows the potential utility of this device, especially for facilitating decentralization of CD4 testing services in rural areas.

scholarly journals Environmental surveillance for Salmonella Typhi as a tool to estimate the incidence of typhoid fever in low-income populations

2021 ◽  
Author(s):  
Christopher B Uzzell ◽  
Catherine M Troman ◽  
Jonathan Rigby ◽  
Venkata Raghava Mohan ◽  
Jacob John ◽  
...  
Keyword(s):  
Typhoid Fever ◽  
Low Income ◽  
Low Cost ◽  
World Health ◽  
Low Income Countries ◽  
Environmental Surveillance ◽  
Sample Collection ◽  
Conjugate Vaccines ◽  
Clinical Surveillance ◽  
The Impact

Background: The World Health Organisation recommends prioritised use of recently prequalified typhoid conjugate vaccines in countries with the highest incidence of typhoid fever. However, representative typhoid surveillance data are lacking in many low-income countries because of the costs and challenges of diagnostic clinical microbiology. Environmental surveillance (ES) of Salmonella Typhi in sewage and wastewater using molecular methods may offer a low-cost alternative, but its performance in comparison with clinical surveillance has not been assessed. Methodology/Principal Findings: We developed a harmonised protocol for typhoid ES and its implementation in communities in India and Malawi where it will be compared with findings from hospital-based surveillance for typhoid fever. The protocol includes methods for ES site selection based on geospatial analysis, grab and trap sample collection at sewage and wastewater sites, and laboratory methods for sample processing, concentration and quantitative PCR to detect Salmonella Typhi. The optimal locations for ES sites based on digital elevation models and mapping of sewage and river networks are described for each community and their suitability confirmed through field investigation. We will compare the prevalence and abundance of Salmonella Typhi in ES samples collected each month over a 12-month period to the incidence of blood culture confirmed typhoid estimated from cases recorded at referral hospitals serving the study areas and community surveys of healthcare seeking for individuals with fever. Significance: If environmental detection of Salmonella Typhi correlates with the incidence of typhoid fever estimated through clinical surveillance, typhoid ES may be a powerful and low-cost tool to estimate the local burden of typhoid fever and support the introduction of typhoid conjugate vaccines. Typhoid ES could also allow the impact of vaccination to be assessed and rapidly identify circulation of drug resistant strains.

scholarly journals A Pediatric Sepsis Protocol Reduced Mortality and Dysfunctions in a Brazilian Public Hospital

2021 ◽  
Vol 9 ◽  
Author(s):  
Daniela Nasu Monteiro Medeiros ◽  
Ana Carolina Cintra Nunes Mafra ◽  
Joseph Anthony Carcillo ◽  
Eduardo Juan Troster
Keyword(s):  
Septic Shock ◽  
Severe Sepsis ◽  
Low Income ◽  
Public Hospital ◽  
Propensity Score Analysis ◽  
Low Cost ◽  
Venous Blood ◽  
Blood Gases ◽  
Lower Probability ◽  
Sepsis Bundles

Introduction: Few studies in the literature discuss the benefits of compliance with sepsis bundles in hospitals in low- and middle-income countries, where resources are limited and mortality is high.Methods: This is a retrospective cohort study conducted at a public hospital in a low-income region in Brazil. We evaluated whether completion of a sepsis bundle is associated with reduced in-hospital mortality for sepsis, severe sepsis, and septic shock, as well as prevention of septic shock and organ dysfunction. Bundle compliance required the completion of three items: (1) obtaining blood count and culture, arterial or venous blood gases, and arterial or venous lactate levels; (2) antibiotic infusion within the first hour of diagnosis; and (3) infusion of 10–20 ml/kg saline solution within the first hour of diagnosis.Results: A total of 548 children with sepsis, severe sepsis, or septic shock who were treated at the emergency room from February 2008 to August of 2016 were included in the study. Of those, 371 patients were included in the protocol group and had a lower median length of stay (3 days vs. 11 days; p < 0.001), fewer organ dysfunctions during hospitalization (0 vs. 2, p < 0.001), and a lower probability of developing septic shock. According to a propensity score analysis, mortality was lower during the post-implementation period [2.75 vs. 15.4% (RR 95%IC 0.13 (0.06, 0.27); p < 0.001)].Conclusions: A simple and low-cost protocol was feasible and yielded good results at a general hospital in a low-income region in Brazil. Protocol use resulted in decreased mortality and progression of dysfunctions and was associated with a reduced probability of developing septic shock.

scholarly journals A serological assay to detect SARS-CoV-2 antibodies in at-home collected finger-prick dried blood spots

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Donna Grace Karp ◽  
Kenneth Danh ◽  
Noemi Fonseca Espinoza ◽  
David Seftel ◽  
Peter V. Robinson ◽  
...  
Keyword(s):  
Large Scale ◽  
Health Care Systems ◽  
Dried Blood Spots ◽  
Sample Collection ◽  
The Us ◽  
Finger Prick ◽  
Care Systems ◽  
Hard To Reach Populations ◽  
Development And Validation ◽  
At Home

AbstractAccurate surveillance of coronavirus disease 2019 (COVID-19) incidence requires large-scale testing of the population. Current testing methods require in-person collection of biospecimens by a healthcare worker, limiting access of individuals who do not have access to testing facilities while placing both patients and healthcare workers at risk of exposure to infection. We report the development and validation of a at-home finger-prick dried blood spot collection kit and an analysis method. We demonstrated 100% sensitivity and specificity using at-home collected specimens across the US. Such methods may facilitate the conduct of unbiased serosurveys within hard to reach populations and help reduce the sample collection burden of serological testing on both health care systems and individuals alike.

scholarly journals PRODUKSI ANTISERUM DAN KAJIAN SEROLOGI CHRYSANTHEMUM B CARLAVIRUS (CVB)

2010 ◽  
Vol 10 (1) ◽  
pp. 80-88
Author(s):  
IGRM Temaja ◽  
G. Suastika ◽  
S.H. Hidayat ◽  
U. Kartosuwondo
Keyword(s):  
Guinea Pig ◽  
Large Scale ◽  
Serological Test ◽  
Low Cost ◽  
Virus Detection ◽  
High Sensitivity ◽  
Serological Assay ◽  
Virus Identification ◽  
Plant Virus Detection ◽  
And Storage

Antiserum production and serological assay of Chrysanthemum B Carlavirus (CVB). Virus identification based on spesific reaction between antigen and antibody  in serological assay has been widely applied as a tool for plant virus detection. The aims of this research is  to produce  antiserum of the CVB by  guinea pig immunization using  purified CVB of Cianjur isolate. The antiserum   was used further  for  the  serological test. Serological methods for detection of CVB were I-ELISA, TBIA, western blot and ISEM. The result showed that  guinea pig immunization  using 150 µg of purified virus was able to produce 10.75 ml of antiserum. The antiserum produced had high sensitivity for detection of CVB when examined by I-ELISA and TBIA. Besides its low cost, TBIA allows the samples to be blotted on the nitrocellulose membranes in the field and storage of the membranes for later processing in the laboratory. This feature makes it the metode of  choice for large-scale CVB surveying.

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