scholarly journals Amplified parallel antigen rapid test for point-of-care salivary detection of SARS-CoV-2 with improved sensitivity

2021 ◽  
Vol 189 (1) ◽  
Author(s):  
Danny Jian Hang Tng ◽  
Bryan Chu Yang Yin ◽  
Jing Cao ◽  
Kwan Ki Karrie Ko ◽  
Kenneth Choon Meng Goh ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Rapid Test ◽  
Spike Protein ◽  
Angiotensin Converting Enzyme 2 ◽  
Resource Limited ◽  
Order Of Magnitude ◽  
Rapid Tests ◽  
Point Of Care Tests ◽  
Control Study

AbstractIn the ongoing COVID-19 pandemic, simple, rapid, point-of-care tests not requiring trained personnel for primary care testing are essential. Saliva-based antigen rapid tests (ARTs) can fulfil this need, but these tests require overnight-fasted samples; without which independent studies have demonstrated sensitivities of only 11.7 to 23.1%. Herein, we report an Amplified Parallel ART (AP-ART) with sensitivity above 90%, even with non-fasted samples. The virus was captured multimodally, using both anti-spike protein antibodies and Angiotensin Converting Enzyme 2 (ACE2) protein. It also featured two parallel flow channels. The first contained spike protein binding gold nanoparticles which produced a visible red line upon encountering the virus. The second contained signal amplifying nanoparticles that complex with the former and amplify the signal without any linker. Compared to existing dual gold amplification techniques, a limit of detection of one order of magnitude lower was achieved (0.0064 ng·mL–1). AP-ART performance in detecting SARS-CoV-2 in saliva of COVID-19 patients was investigated using a case–control study (139 participants enrolled and 162 saliva samples tested). Unlike commercially available ARTs, the sensitivity of AP-ART was maintained even when non-fasting saliva was used. Compared to the gold standard reverse transcription-polymerase chain reaction testing on nasopharyngeal samples, non-fasting saliva tested on AP-ART showed a sensitivity of 97.0% (95% CI: 84.7–99.8); without amplification, the sensitivity was 72.7% (95% CI: 83.7–94.8). Thus, AP-ART has the potential to be developed for point-of-care testing, which may be particularly important in resource-limited settings, and for early diagnosis to initiate newly approved therapies to reduce COVID-19 severity. Graphical abstract

scholarly journals Comparison of seven commercial SARS-CoV-2 rapid Point-of-Care Antigen tests

2020 ◽  
Author(s):  
Victor M. Corman ◽  
Verena Claudia Haage ◽  
Tobias Bleicker ◽  
Marie Luisa Schmidt ◽  
Barbara Mühlemann ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Rapid Test ◽  
Infectious Period ◽  
Clinical Samples ◽  
Virus Concentration ◽  
Viral Loads ◽  
And Performance ◽  
Antigen Tests ◽  
Point Of Care Tests

AbstractBackgroundAntigen point of care tests (AgPOCT) can accelerate SARS-CoV-2 testing. As first AgPOCT are becoming available, there is a growing interest in their utility and performance.MethodsHere we compare AgPOCT products by seven suppliers: the Abbott Panbio™ COVID-19 Ag Rapid Test; the RapiGEN BIOCREDIT COVID-19 Ag; the Healgen® Coronavirus Ag Rapid Test Cassette (Swab); the Coris Bioconcept Covid.19 Ag Respi-Strip; the R-Biopharm RIDA®QUICK SARS-CoV-2 Antigen; the NAL von minden NADAL COVID19-Ag Test; and the Roche/SD Biosensor SARS-CoV Rapid Antigen Test. Tests were evaluated on recombinant nucleoprotein, cultured endemic and emerging coronaviruses, stored clinical samples with known SARS-CoV-2 viral loads (n=138), stored samples from patients with respiratory agents other than SARS-CoV-2 (n=100), as well as self-sampled swabs from healthy volunteers (n=35).FindingsLimits of detection in six of seven tested products ranged between 2.08 × 106 and 2.88 × 107 copies per swab, the outlier at 1.58 × 1010 copies per swab. Specificities ranged between 98.53% and 100% in five products, with two outliers at 94.85% and 88.24%. False positive results were not associated with any specific respiratory agent. As some of the tested AgPOCT were early production lots, the observed issues with specificity are unlikely to persist.InterpretationThe sensitivity range of most AgPOCT overlaps with viral load figures typically observed during the first week of symptoms, which marks the infectious period in the majority patients. AgPOCTs with a limit of detection that approximates the virus concentration above which patients are infectious may enable shortcuts in decision-making in various areas of healthcare and public health.

scholarly journals Fast Procedures for the Electrodeposition of Platinum Nanostructures on Miniaturized Electrodes for Improved Ion Sensing

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2260 ◽  
Author(s):  
Francesca Criscuolo ◽  
Irene Taurino ◽  
Van Dam ◽  
Francky Catthoor ◽  
Marcel Zevenbergen ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Electrochemical Behaviour ◽  
Linear Sweep Voltammetry ◽  
Metal Nanostructures ◽  
Ion Sensing ◽  
Dry Conditions ◽  
Order Of Magnitude ◽  
Constant Potential ◽  
Nanostructured Layers

Nanostructured materials have attracted considerable interest over the last few decades to enhance sensing capabilities thanks to their unique properties and large surface area. In particular, noble metal nanostructures offer several advantages including high stability, non-toxicity and excellent electrochemical behaviour. However, in recent years the great expansion of point-of-care (POC) and wearable systems and the attempt to perform measurements in tiny spaces have also risen the need of increasing sensors miniaturization. Fast constant potential electrodeposition techniques have been proven to be an efficient way to obtain conformal platinum and gold nanostructured layers on macro-electrodes. However, this technique is not effective on micro-electrodes. In this paper, we investigate an alternative one-step deposition technique of platinum nanoflowers on micro-electrodes by linear sweep voltammetry (LSV). The effective deposition of platinum nanoflowers with similar properties to the ones deposited on macro-electrodes is confirmed by morphological analysis and by the similar roughness factor (~200) and capacitance (~18 μ F/mm 2 ). The electrochemical behaviour of the nanostructured layer is then tested in an solid-contact (SC) L i + -selective micro-electrode and compared to the case of macro-electrodes. The sensor offers Nernstian calibration with same response time (~15 s) and a one-order of magnitude smaller limit of detection (LOD) ( 2.6 × 10 − 6 ) with respect to the macro-ion-selective sensors (ISE). Finally, sensor reversibility and stability in both wet and dry conditions is proven.

scholarly journals Is There a Role of Using a Rapid Finger Prick Antibody Test in Screening for Celiac Disease in Children?

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
Kristina Baraba Dekanić ◽  
Ivona Butorac Ahel ◽  
Lucija Ružman ◽  
Jasmina Dolinšek ◽  
Jernej Dolinšek ◽  
...  
Keyword(s):  
Celiac Disease ◽  
Point Of Care ◽  
Tissue Transglutaminase ◽  
Rapid Test ◽  
Antibody Test ◽  
First Grade ◽  
Iga Deficiency ◽  
Iga Antibodies ◽  
Point Of Care Tests

Introduction. Celiac disease (CD) is an autoimmune disease triggered by gluten in genetically predisposed individuals. Despite the increasing prevalence of CD, many patients remain undiagnosed. Standard serology tests are expensive and invasive, so several point-of-care tests (POC) for CD have been developed. We aimed to determine the prevalence of CD in first-grade pupils in Primorje-Gorski Kotar County, Croatia, using a POC test. Methods. A Biocard celiac test that detects IgA antibodies to tissue transglutaminase in whole blood was used to screen for celiac disease in healthy first-grade children born in 2011 and 2012 who consumed gluten without restrictions. Results. 1478 children were tested, and none of them were tested positive with a rapid test. In 10 children (0,6%), IgA deficiency has been suspected; only 4 of them agreed to be tested further for total IgA, anti-tTG, and anti-DGP antibodies. IgA deficiency was confirmed in 3 patients, and in all 4 children, CD has been excluded. Conclusion. Our results have not confirmed the usefulness of the POC test in screening the general population of first-grade schoolchildren. Further research is needed to establish the true epidemiology of CD in Primorje-Gorski Kotar County and to confirm the value of the rapid test in comparison with standard antibody CD testing.

scholarly journals Are Treponema pallidum Specific Rapid and Point-of-Care Tests for Syphilis Accurate Enough for Screening in Resource Limited Settings? Evidence from a Meta-Analysis

PLoS ONE ◽  
2013 ◽  
Vol 8 (2) ◽  
pp. e54695 ◽  
Author(s):  
Yalda Jafari ◽  
Rosanna W. Peeling ◽  
Sushmita Shivkumar ◽  
Christiane Claessens ◽  
Lawrence Joseph ◽  
...  
Keyword(s):  
Point Of Care ◽  
Meta Analysis ◽  
Treponema Pallidum ◽  
Resource Limited Settings ◽  
Resource Limited ◽  
Point Of Care Tests

scholarly journals Diagnostic accuracy of two commercial SARS-CoV-2 Antigen-detecting rapid tests at the point of care in community-based testing centers

2020 ◽  
Author(s):  
Alice Berger ◽  
Marie Therese Ngo Nsoga ◽  
Francisco Javier Perez-Rodriguez ◽  
Yasmine Abi Aad ◽  
Pascale Sattonnet-Roche ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
Point Of Care ◽  
Rapid Test ◽  
Diagnostic Value ◽  
Rapid Diagnostic Tests ◽  
Ease Of Use ◽  
Rt Pcr ◽  
Test Device ◽  
Community Based ◽  
Rapid Tests

AbstractBackgroundAntigen-detecting rapid diagnostic tests for SARS-CoV-2 offer new opportunities for the quick and laboratory-independent identification of infected individuals for control of the SARS-CoV-2 pandemic.MethodsWe performed a prospective, single-center, point of care validation of two antigen-detecting rapid diagnostic tests (Ag-RDT) in comparison to RT-PCR on nasopharyngeal swabs.FindingsBetween October 9th and 23rd, 2020, 1064 participants were enrolled. The Panbio™Covid-19 Ag Rapid Test device (Abbott) was validated in 535 participants, with 106 positive Ag-RDT results out of 124 positive RT-PCR individuals, yielding a sensitivity of 85.5% (95% CI: 78.0–91.2). Specificity was 100.0% (95% CI: 99.1–100) in 411 RT-PCR negative individuals. The Standard Q Ag-RDT (SD Biosensor, Roche) was validated in 529 participants, with 170 positive Ag-RDT results out of 191 positive RT-PCR individuals, yielding a sensitivity of 89.0% (95%CI: 83.7–93.1). One false positive result was obtained in 338 RT-PCR negative individuals, yielding a specificity of 99.7% (95%CI: 98.4–100). For individuals presenting with fever 1-5 days post symptom onset, combined Ag-RDT sensitivity was above 95%.InterpretationWe provide an independent validation of two widely available commercial Ag-RDTs, both meeting WHO criteria of ≥80% sensitivity and ≥97% specificity. Although less sensitive than RT-PCR, these assays could be beneficial due to their rapid results, ease of use, and independence from existing laboratory structures. Testing criteria focusing on patients with typical symptoms in their early symptomatic period onset could further increase diagnostic value.FundingFoundation of Innovative Diagnostics (FIND), Fondation privée des HUG, Pictet Charitable Foundation.

scholarly journals Diagnostic accuracy of two commercial SARS-CoV-2 antigen-detecting rapid tests at the point of care in community-based testing centers

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248921
Author(s):  
Alice Berger ◽  
Marie Therese Ngo Nsoga ◽  
Francisco Javier Perez-Rodriguez ◽  
Yasmine Abi Aad ◽  
Pascale Sattonnet-Roche ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Point Of Care ◽  
Rapid Test ◽  
Diagnostic Value ◽  
Ease Of Use ◽  
Lower Sensitivity ◽  
Rt Pcr ◽  
Test Device ◽  
Community Based ◽  
Rapid Tests

Objectives Determine the diagnostic accuracy of two antigen-detecting rapid diagnostic tests (Ag-RDT) for SARS-CoV-2 at the point of care and define individuals’ characteristics providing best performance. Methods We performed a prospective, single-center, point of care validation of two Ag-RDT in comparison to RT-PCR on nasopharyngeal swabs. Results Between October 9th and 23rd, 2020, 1064 participants were enrolled. The PanbioTM Covid-19 Ag Rapid Test device (Abbott) was validated in 535 participants, with 106 positive Ag-RDT results out of 124 positive RT-PCR individuals, yielding a sensitivity of 85.5% (95% CI: 78.0–91.2). Specificity was 100.0% (95% CI: 99.1–100) in 411 RT-PCR negative individuals. The Standard Q Ag-RDT (SD Biosensor, Roche) was validated in 529 participants, with 170 positive Ag-RDT results out of 191 positive RT-PCR individuals, yielding a sensitivity of 89.0% (95%CI: 83.7–93.1). One false positive result was obtained in 338 RT-PCR negative individuals, yielding a specificity of 99.7% (95%CI: 98.4–100). For individuals presenting with fever 1–5 days post symptom onset, combined Ag-RDT sensitivity was above 95%. Lower sensitivity of 88.2% was seen on the same day of symptom development (day 0). Conclusions We provide an independent validation of two widely available commercial Ag-RDTs, both meeting WHO criteria of ≥80% sensitivity and ≥97% specificity. Although less sensitive than RT-PCR, these assays could be beneficial due to their rapid results, ease of use, and independence from existing laboratory structures. Testing criteria focusing on patients with typical symptoms in their early symptomatic period onset could further increase diagnostic value.

Sensitivity of the STAT-VIEW rapid self-test and implications for use during acute HIV infection

2017 ◽  
Vol 94 (7) ◽  
pp. 475-478 ◽  
Author(s):  
Narjis Boukli ◽  
Anders Boyd ◽  
Noémie Wendremaire ◽  
Pierre-Marie Girard ◽  
Julie Bottero ◽  
...  
Keyword(s):  
Hiv Infection ◽  
Point Of Care ◽  
Rapid Test ◽  
Detection Sensitivity ◽  
Serum Samples ◽  
Acute Hiv Infection ◽  
Hiv Rna ◽  
Rapid Tests ◽  
Acute Hiv ◽  
Self Test

ObjectivesHIV testing is an important step towards diminishing incident infections. Rapid self-tests whose use is becoming more common in France could help increase access to testing, yet could fail to diagnose HIV during acute HIV infection (AHI). The aim of the present study was to evaluate HIV-detection sensitivity of a commonly used rapid self-test (STAT-VIEW HIV1/2), compared with another point-of-care rapid test (INSTI), among patients presenting with AHI.MethodsIndividuals tested at Saint-Antoine Hospital (Paris, France) with negative or indeterminate western blot (WB) results and detectable HIV-RNA were included. Rapid tests were performed retrospectively on stored serum. Patients with and without reactive rapid tests were compared, while probability of having a reactive test was modelled across infection duration using logistic regression.ResultsOf the 40 patients with AHI, 23 (57.5%) had a reactive STAT-VIEW rapid test. Patients with non-reactive versus reactive tests had a significantly shorter median time since infection (p=0.01), time since onset of symptoms (p=0.009), higher proportion with Fiebig stage III versus IV (p=0.003), negative WB results (p=0.007), higher HIV-RNA levels (p=0.001) and lower CD4+ and CD8+ cell count (p=0.03, p<0.001, respectively). When examining sensitivity over the course of AHI duration, the probability of HIV detection was 75.5% at 5 weeks from HIV transmission. The INSTI provided similar results with respect to proportion of reactive tests (62.5%), determinants for non-reactive test and probability of HIV detection at 5 weeks of infection (85.0%).ConclusionsOver half of AHI patients had reactive serology using the STAT-VIEW rapid self-test when performed on serum samples. Considering that detection sensitivity increased substantially over infection time, individuals should not rely on a negative result to accurately exclude HIV infection within at least 5 weeks of potential HIV exposure. Notwithstanding strong recommendations against rapid test use during AHI, some utility in detecting HIV is observed 5–12 weeks after transmission.

Investigations and microscopy

2019 ◽  
pp. 63-80
Keyword(s):  
Nucleic Acid ◽  
Laboratory Testing ◽  
Trichomonas Vaginalis ◽  
Point Of Care ◽  
Rapid Test ◽  
The Other ◽  
Nucleic Acid Amplification ◽  
Blood Samples ◽  
Dark Ground ◽  
Point Of Care Tests

This chapter covers investigations and tests commonly used in sexual health. Some investigations can be performed on-site as the patient waits, such as urinalysis, pregnancy tests, and increasingly available point of care tests for infections such as HIV and, less commonly, the other blood-borne viruses, syphilis, Trichomonas vaginalis. On-site microscopy helps with diagnosis of genital candidiasis, bacterial vaginosis, N. gonorrhoeae infection, and T. vaginalis. Other investigations require sending samples away for laboratory testing of genital or ulcer swab, urine, or blood samples for STI and blood-borne viruses. This chapter explains the use of light and dark ground microscopy, near patient rapid test technologies, molecular methods such as nucleic acid amplification, culture and serology. Sensitivities and specificities of commonly available test kits are included.

scholarly journals Inkjet printing of paraffin on paper allows low-cost point-of-care diagnostics for pathogenic fungi

Cellulose ◽  
2020 ◽  
Vol 27 (13) ◽  
pp. 7691-7701 ◽  
Author(s):  
Anusha Prabhu ◽  
M. S. Giri Nandagopal ◽  
Prakash Peralam Yegneswaran ◽  
Hardik Ramesh Singhal ◽  
Naresh Kumar Mani
Keyword(s):  
Filter Paper ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Pathogenic Fungi ◽  
Sem Analysis ◽  
Qualitative Assessment ◽  
Resource Limited ◽  
Hydrophobic Barrier ◽  
Pore Blockage

Abstract We present a high resolution, ultra-frugal printing of paper microfluidic devices using in-house paraffin formulation on a simple filter paper. The patterns printed using an office inkjet printer formed a selective hydrophobic barrier of 4 ± 1 µm thickness with a hydrophilic channel width of 275 µm. These printed patterns effectively confine common aqueous solutions and solvents, which was verified by solvent compatibility studies. SEM analysis reveals that the solvent confinement is due to pore blockage in the filter paper. The fabricated paper-based device was validated for qualitative assessment of Candida albicans (pathogenic fungi) by using a combination of L-proline β-naphthylamide as the substrate and cinnamaldehyde as an indicator. Our studies reveal that the pathogenic fungi can be detected within 10 min with the limit of detection (LOD) of 0.86 × 106 cfu/mL. Owing to its simplicity, this facile method shows high potential and can be scaled up for developing robust paper-based devices for biomarker detection in resource-limited settings. Graphic abstract

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