scholarly journals Point-of-Care Strategies Applied to Malaria Diagnosis

2021 ◽  
Author(s):  
Alexandre Dias Tavares Costa ◽  
Anna Caroline Campos Aguiar ◽  
Angelina Moraes Silva ◽  
Dhelio Batista Pereira
Keyword(s):  
Gold Standard ◽  
Diagnostic Tests ◽  
Point Of Care ◽  
Low Cost ◽  
Malaria Diagnosis ◽  
Standard Test ◽  
Mixed Infections ◽  
Specific Diagnosis ◽  
Disease Diagnostics ◽  
Drop Technique

Rapid and specific diagnosis of malaria remains one of the main strategies to fight the disease. The diagnosis is made primarily by the simple and low-cost thick drop technique, considered the gold standard test. However, the requirement for good quality microscopes and well-trained personnel often lead to inaccurate diagnosis, especially in cases of mixed infections or low parasitemia. Although PCR-based tests can help in these situations, this technique requires large and sensitive equipments, being unsuitable for point of care (POC) settings. A myriad of POC diagnostic tests have being developed in the last years, relying on molecular methods but also on novel strategies. New platforms, miniaturization techniques, and multiplexing possibilities promise great potential to improve disease diagnostics through fast and accurate detection of cases, even at remote places. Here, we will address the main POC strategies developed for the diagnosis of malaria, highlighting their strengths and weakness as POC applications.

The diagnostic performance of rapid diagnostic tests and microscopy for malaria diagnosis in eastern Sudan using a nested polymerase chain reaction assay as a reference standard

2019 ◽  
Vol 113 (11) ◽  
pp. 701-705 ◽  
Author(s):  
Zakya A Abdalla ◽  
NourElhouda A Rahma ◽  
Elhashimi E Hassan ◽  
Tajeldin M Abdallah ◽  
Hadeel E Hamad ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Gold Standard ◽  
Diagnostic Tests ◽  
Diagnostic Performance ◽  
Malaria Diagnosis ◽  
Rapid Diagnostic Tests ◽  
Chain Reaction ◽  
Nested Polymerase Chain Reaction ◽  
Polymerase Chain ◽  
Eastern Sudan

Abstract Background Accurate diagnosis of malaria infection is essential for successful control and management of the disease. Both microscopy and rapid diagnostic tests (RDTs) are recommended for malaria diagnosis, however, RDTs are more commonly used. The aim of the current study was to assess the performance of microscopy and RDTs in the diagnosis of Plasmodium falciparum infection using a nested polymerase chain reaction (PCR) assay as the gold standard. Methods A cross-sectional study was carried out in Kassala Hospital, eastern Sudan. A total of 341 febrile participants of all ages were recruited. Blood specimens were collected and malaria testing was performed using an RDT (SD Bioline Malaria Ag Pf), microscopy and nested PCR. The sensitivity, specificity, positive and negative predictive values (PPV and NPV, respectively) of microscopy and the RDT were investigated. Results The prevalence of P. falciparum malaria infections in this study was 22.9%, 24.3% and 26.7% by PCR, microscopy and RDT, respectively. Compared with microscopy, the RDT had slightly higher sensitivity (80.7% vs 74.3%; p=0.442), equivalent specificity (89.3% vs 90.4%), a similar PPV (69.2% vs 69.8%) and a higher NPV (94.0% vs 92.2%). Conclusions The diagnostic performance of the RDT was better than that of microscopy in the diagnosis of P. falciparum malaria when nested PCR was used as the gold standard.

scholarly journals Aptamers that bind filovirus GP : a new frontier for detection and neutralization of Ebola and Marburg virus

2020 ◽  
Author(s):  
◽  
Kwaku Dwumah Tawiah
Keyword(s):  
Point Of Care ◽  
Low Cost ◽  
Marburg Virus ◽  
Whole Cells ◽  
Affinity Enrichment ◽  
Disease Diagnostics ◽  
Individual Sequences ◽  
The Individual ◽  
And Function

Aptamers are single chained, nucleic acid-based affinity probes that bind to their targets with strong affinity and specificity. They are made through an in vitro combinatorial selection method, wherein large libraries of nucleic acids with randomized sequences are subjected to an iterative process of affinity enrichment, partitioning, and amplification. Evolved libraries are sequenced, and the individual sequences are screened and characterized for their structure and function. Aptamers have been developed to target many molecules, including small molecules, purified proteins, whole cells, bacteria, and viruses. They have been developed for therapeutics and as research and diagnostic probes. Aptamers that have an affinity for virus surfaces are excellent probes for developing low-cost biosensors and potentially antiviral therapeutics. In this work, I present the development of aptamers that have an affinity for filovirus surfaces. I first describe the development of an improved method for purifying highly lytic vesicular stomatitis virus-based filovirus GP displayed surrogate viruses. Filoviruses are highly pathogenic and thus require highly secured containment facilities for their studies. The use of attenuated surrogates facilitates filovirus research at biosafety level 2 facilities. This work outlines the steps required to propagate and generate pure virus particles to be used as selection targets. I then describe the development of aptamer probes that differentially recognize GPs from MARV and EBOV. This work represents the first step in the development of aptamer based-low-cost point of care devices for filovirus disease diagnostics. Finally, this work describes the use of a hybrid selection approach that combines two different selection platforms to generate aptamers that bind to EBOV surfaces.

scholarly journals Anemia Diagnosis on a Simple Paper-based Assay

2018 ◽  
Author(s):  
Sujay K Biswas ◽  
Soumya Bandyopadhyay ◽  
Shantimoy Kar ◽  
Nirmal K Som ◽  
Suman Chakraborty
Keyword(s):  
Gold Standard ◽  
Diagnostic Tests ◽  
State Of The Art ◽  
Wide Spectrum ◽  
Point Of Care ◽  
Test Method ◽  
High Fidelity ◽  
Neonatal Mortality Rate ◽  
Blood Samples ◽  
Mild Anemia

AbstractIn developing countries, the maternal and neonatal mortality rate is often affected by prenatal period anemia, a preventable and ubiquitous impairment attributed due to low hemoglobin (Hgb) concentration. We report the development of a simple, frugal (~ 0.02 $ per test), rapid and high fidelity paper-based colorimetric microfluidic device for point-of-care (POC) detection of anemia. We validate our findings with 32 blood samples collected from different patients covering a wide spectrum of anemia and subsequently, compare with standard pathological results measured using a hematology analyzer. POC based Hgb estimates are correlated with the pathological gold standard estimates of Hgb levels (r = 0.909), and the POC test method yielded similar sensitivity and specificity for detecting mild anemia (n = 8) (<11 g/dl) (sensitivity: 87.5%, specificity: 100 %) and for severe anemia (n = 3) (<7 g/dl) (sensitivity: 100 %, specificity: 100 %). The estimated Hgb levels are, within 1.5 g/dl from the pathological estimate, for 91 % of the blood samples. Results demonstrate the elevated efficacy and viability of this POC colorimetric diagnostic test, in comparison to the state-of-the-art complex and expensive diagnostic tests for anemia detection.

scholarly journals Serological determinants of COVID-19

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Annalisa Noce ◽  
Maria Luisa Santoro ◽  
Giulia Marrone ◽  
Cartesio D’Agostini ◽  
Ivano Amelio ◽  
...  
Keyword(s):  
Gold Standard ◽  
Point Of Care ◽  
Standard Test ◽  
Serological Tests ◽  
Point Of Care Test ◽  
Global Pandemic ◽  
Chemiluminescent Immunoassay ◽  
Low Sensitivity ◽  
Short Time

Abstract Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection spreaded rapidly worldwide, as far as it has become a global pandemic. Therefore, the introduction of serological tests for determination of IgM and IgG antibodies has become the main diagnostic tool, useful for tracking the spread of the virus and for consequently allowing its containment. In our study we compared point of care test (POCT) lateral flow immunoassay (FIA) vs automated chemiluminescent immunoassay (CLIA), in order to assess their specificity and sensibility for COVID-19 antibodies detection. Results We find that different specificities and sensitivities for IgM and IgG tests. Notably IgM POCT FIA method vs CLIA method (gold standard) has a low sensitivity (0.526), while IgG POCT FIA method vs CLIA method (gold standard) test has a much higher sensitivity (0.937); further, with respect of IgG, FIA and CLIA could arguably provide equivalent information. Conclusions FIA method could be helpful in assessing in short time, the possible contagiousness of subjects that for work reasons cannot guarantee “social distancing”.

scholarly journals Serological Determinants of COVID-19

2020 ◽  
Author(s):  
Annalisa Noce ◽  
Maria Luisa Santoro ◽  
Giulia Marrone ◽  
Cartesio D’Agostini ◽  
Ivano Amelio ◽  
...  
Keyword(s):  
Gold Standard ◽  
Point Of Care ◽  
Standard Test ◽  
Serological Tests ◽  
Point Of Care Test ◽  
Global Pandemic ◽  
Chemiluminescent Immunoassay ◽  
Low Sensitivity ◽  
Short Time

Abstract Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection spreaded rapidly worldwide, as far as it has become a global pandemic. Therefore, the introduction of serological tests useful for the determination of IgM and IgG antibodies, it has become the main diagnostic tool, useful for tracking the spread of the virus and consequently its containment. In our study we compared point of care test (POCT) lateral flow immunoassay (FIA) vs automated chemiluminescent immunoassay (CLIA), in order to assess their specificity and sensibility against COVID-19 antibodies detection. Results: We find that different specificities and sensitivities for IgG and IgM tests. Notably IgM POCT FIA method vs CLIA method (gold standard) has a low sensitivity (0.526), while POCT FIA method vs CLIA method (gold standard) test has a much higher sensitivity (0.937); further, with respect of IgG, FIA and CLIA could arguably provide the same information. Conclusions: FIA method could be helpful in assessing in short time, the possible contagiousness of subjects that for work reasons cannot guarantee “social distancing”.

Comparative Efficacy of Canine Parvovirus-2 Infection Diagnostic Tests Commonly Prevailing in India

2019 ◽  
Vol 14 (04) ◽  
Author(s):  
P. R. Dorlikar ◽  
S. R. Warke ◽  
U. M. Tumlam ◽  
V. C. Ingle
Keyword(s):  
Disease Transmission ◽  
Diagnostic Tests ◽  
Low Cost ◽  
Standard Test ◽  
Antigen Detection ◽  
Comparative Efficacy ◽  
Preliminary Screening ◽  
Gold Standard Test ◽  
Pcr Method ◽  
Polymerase Chain

Early and rapid field diagnosis of CPV-2 infection is essential for preventing disease transmission from infected to susceptible dogs. In the present study total 91 fecal samples and rectal swabs collected from a diarrheic and non-diarrheic dog from clinics located in and around Nagpur. Polymerase Chain Reaction Rapid Antigen detection kit, and Haemagglutination test (HA) were able to detect CPV-2 in 41 (45.05%), 34 (37.36%) and 22 (24.17%) samples, respectively. The evaluation revealed that the PCR method was found to be most sensitive followed by antigen detection kit and HA field test. Sensitivity and specificity of antigen detection kit with respect to PCR method were found to be 78.08% and 96.00%, respectively. The finding suggests PCR with the highest sensitivity may be taken as a gold standard test of CPV-2 relative to other diagnostic tests. HA test could be employed for the preliminary screening in field because of its rapid response and low cost.

scholarly journals Paper-Based Point-of-Care Testing of SARS-CoV-2

2021 ◽  
Vol 9 ◽  
Author(s):  
Yuan Jia ◽  
Hao Sun ◽  
Jinpeng Tian ◽  
Qiuming Song ◽  
Wenwei Zhang
Keyword(s):  
Diagnostic Tests ◽  
State Of The Art ◽  
Point Of Care ◽  
Low Cost ◽  
The State ◽  
Detection Methods ◽  
Point Of Care Testing ◽  
Research Opportunities ◽  
Acute Infections ◽  
Reliable Detection

The COVID-19 pandemic has resulted in significant global social and economic disruption. The highly transmissive nature of the disease makes rapid and reliable detection critically important. Point-of-care (POC) tests involve performing diagnostic tests outside of a laboratory that produce a rapid and reliable result. It therefore allows the diagnostics of diseases at or near the patient site. Paper-based POC tests have been gaining interest in recent years as they allow rapid, low-cost detection without the need for external instruments. In this review, we focus on the development of paper-based POC devices for the detection of SARS-CoV-2. The review first introduces the principles of detection methods that are available to paper-based devices. It then summarizes the state-of-the-art paper devices and their analytical performances. The advantages and drawbacks among methods are also discussed. Finally, limitations of the existing devices are discussed, and prospects are given with the hope to identify research opportunities and directions in the field. We hope this review will be helpful for researchers to develop a clinically useful and economically efficient paper-based platform that can be used for rapid, accurate on-site diagnosis to aid in identifying acute infections and eventually contain the COVID-19 pandemic.

Low-Cost Thermal Shield for Rapid Diagnostic Tests Using Phase Change Materials

2018 ◽  
Vol 12 (1) ◽  
Author(s):  
Luis R. Soenksen ◽  
David A. Martínez-Corona ◽  
Sofía Iñiguez de Gante ◽  
Pierre S. Phabmixay ◽  
Mauricio J. Marongiu Maggi
Keyword(s):  
Phase Change ◽  
Diagnostic Tests ◽  
Phase Change Materials ◽  
Point Of Care ◽  
Low Cost ◽  
Cost Effective ◽  
Rapid Diagnostic Tests ◽  
Cold Chain ◽  
Thermal Shield ◽  
Tropical Regions

The shelf life of point-of-care and rapid diagnostic tests (POC-RDTs) is commonly compromised by abrupt temperature changes during storage, transportation, and use. This situation is especially relevant in tropical regions and resource-constrained settings where cold chain may be unreliable. Here, we report the use of novel and low-cost passive thermal shield (TS) made from laminated phase change material (PCM) to reduce thermal overload in POC-RDTs. Validation of the proposed design was done through numerical simulation and testing of an octadecane shield prototype in contact with a lateral flow immunoassay. The use of our TS design provided 30–45 min delay in thermal equilibration under constant and oscillating heat load challenges resembling those of field use. The addition of a thin PCM protection layer to POC-RDTs can be a cost-effective, scalable, and reliable solution to provide additional thermal stability to these devices.

scholarly journals A Low-Cost Biological Agglutination Assay for Medical Diagnostic Applications

2018 ◽  
Author(s):  
Nicolas Kylilis ◽  
Pinpunya Riangrungroj ◽  
Hung-En Lai ◽  
Valencio Salema ◽  
Luis Ángel Fernández ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
Point Of Care ◽  
Low Cost ◽  
Field Testing ◽  
Human Fibrinogen ◽  
Detection Range ◽  
Agglutination Assay ◽  
E Coli ◽  
Medical Diagnostic ◽  
Diagnostic Applications

ABSTRACTAffordable, easy-to-use diagnostic tests that can be readily deployed for point-of-care (POC) testing are key in addressing challenges in the diagnosis of medical conditions and for improving global health in general. Ideally, POC diagnostic tests should be highly selective for the biomarker, user-friendly, have a flexible design architecture and a low cost of production. Here we developed a novel agglutination assay based on wholeE. colicells surface-displaying nanobodies which bind selectively to a target protein analyte. As a proof-of-concept, we show the feasibility of this design as a new diagnostic platform by the detection of a model analyte at nanomolar concentrations. Moreover, we show that the design architecture is flexible by building assays optimized to detect a range of model analyte concentrations supported using straight-forward design rules and a mathematical model. Finally, we re-engineerE. colicells for the detection of a medically relevant biomarker by the display of two different antibodies against the human fibrinogen and demonstrate a detection limit as low as 10 pM in diluted human plasma. Overall, we demonstrate that our agglutination technology fulfills the requirement of POC testing by combining low-cost nanobody production, customizable detection range and low detection limits. This technology has the potential to produce affordable diagnostics for both field-testing in the developing world, emergency or disaster relief sites as well as routine medical testing and personalized medicine.

scholarly journals Field validation of a magneto-optical detection device (Gazelle) for portable point-of-care Plasmodium vivax diagnosis

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253232
Author(s):  
Hugo O. Valdivia ◽  
Priyaleela Thota ◽  
Greys Braga ◽  
Leonila Ricopa ◽  
Keare Barazorda ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Sensitivity And Specificity ◽  
Nested Pcr ◽  
Diagnostic Tests ◽  
Point Of Care ◽  
Malaria Diagnosis ◽  
Final Analysis ◽  
Rapid Diagnostic Tests ◽  
Field Validation ◽  
Pcr Assay

A major challenge for malaria is the lack of tools for accurate and timely diagnosis in the field which are critical for case management and surveillance. Microscopy along with rapid diagnostic tests are the current mainstay for malaria diagnosis in most endemic regions. However, these methods present several limitations. This study assessed the accuracy of Gazelle, a novel rapid malaria diagnostic device, from samples collected from the Peruvian Amazon between 2019 and 2020. Diagnostic accuracy was compared against microscopy and two rapid diagnostic tests (SD Bioline and BinaxNOW) using 18ssr nested-PCR as reference test. In addition, a real-time PCR assay (PET-PCR) was used for parasite quantification. Out of 217 febrile patients enrolled and tested, 180 specimens (85 P. vivax and 95 negatives) were included in the final analysis. Using nested-PCR as the gold standard, the sensitivity and specificity of Gazelle was 88.2% and 97.9%, respectively. Using a cutoff of 200 parasites/μl, Gazelle’s sensitivity for samples with more than 200 p/uL was 98.67% (95%CI: 92.79% to 99.97%) whereas the sensitivity for samples lower than 200 p/uL (n = 10) was 12.5% (95%CI: 0.32% to 52.65%). Gazelle’s sensitivity and specificity were statistically similar to microscopy (sensitivity = 91.8, specificity = 100%, p = 0.983) and higher than both SD Bioline (sensitivity = 82.4, specificity = 100%, p = 0.016) and BinaxNOW (sensitivity = 71.8%, specificity = 97.9%, p = 0.002). The diagnostic accuracy of Gazelle for malaria detection in P. vivax infections was comparable to light microscopy and superior to both RDTs even in the presence of low parasitemia infections. The performance of Gazelle makes it a valuable tool for malaria diagnosis and active case detection that can be utilized in different malaria-endemic regions.

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