scholarly journals Clinical evaluation of a RT-LAMP SARS-CoV-2 test for the Point-Of-Care, rapid, low-cost, integrating sample solid phase extraction and on which reagents are lyophilized

2021 ◽  
Author(s):  
E. Coz ◽  
P. Garneret ◽  
E. Martin ◽  
D. F. do Nascimento ◽  
A. Vilquin ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Solid Phase ◽  
Point Of Care ◽  
Low Cost ◽  
Rna Extraction ◽  
Rt Pcr ◽  
Viral Loads ◽  
Point Of Care Test ◽  
Freeze Dried ◽  
Paper Device

ABSTRACTObjectivesDetermine the sensitivity and specificity of a Point-Of-Care test (‘COVIDISC’) for SARS-COV2. The novelty of the test is to integrate, on the same (low-cost) compact plastic/paper device, solid phase RNA extraction and RT-LAMP amplification, all reagents being freeze-dried on it.MethodRetrospective study with a cohort of 99 patients characterized by real-time RT-PCR. The 37 positive naso-pharyngeal samples cover a broad range of viral loads (from 5 gc /µL to 2 106 gc/ µL of sample).ResultsThe COVIDISC found 36 positives (out of 37 by IP4 RT-PCR protocols) and 63 negatives (out of 62 by RT-PCR).ConclusionThe sensitivity of the COVIDISC, found in this 99-patient retrospective study, is 97% and the specificity 100%.

scholarly journals A haemagglutination test for rapid detection of antibodies to SARS-CoV-2

2020 ◽  
Author(s):  
Alain Townsend ◽  
Pramila Rijal ◽  
Julie Xiao ◽  
Tiong Kit Tan ◽  
Kuan-Ying A Huang ◽  
...  
Keyword(s):  
High Performance ◽  
Point Of Care ◽  
Low Cost ◽  
Glycophorin A ◽  
Red Cell ◽  
Special Equipment ◽  
Cell Agglutination ◽  
Haemagglutination Test ◽  
Point Of Care Test ◽  
Laboratory Facilities

ABSTRACTSerological detection of antibodies to SARS-CoV-2 is essential for establishing rates of seroconversion in populations, detection of seroconversion after vaccination, and for seeking evidence for a level of antibody that may be protective against COVID-19 disease. Several high-performance commercial tests have been described, but these require centralised laboratory facilities that are comparatively expensive, and therefore not available universally. Red cell agglutination tests have a long history in blood typing, and general serology through linkage of reporter molecules to the red cell surface. They do not require special equipment, are read by eye, have short development times, low cost and can be applied as a Point of Care Test (POCT). We describe a red cell agglutination test for the detection of antibodies to the SARS-CoV-2 receptor binding domain (RBD). We show that the Haemagglutination Test (“HAT”) has a sensitivity of 90% and specificity of 99% for detection of antibodies after a PCR diagnosed infection. The HAT can be titrated, detects rising titres in the first five days of hospital admission, correlates well with a commercial test that detects antibodies to the RBD, and can be applied as a point of care test. The developing reagent is composed of a previously described nanobody to a conserved glycophorin A epitope on red cells, linked to the RBD from SARS-CoV-2. It can be lyophilised for ease of shipping. We have scaled up production of this reagent to one gram, which is sufficient for ten million tests, at a cost of ∼0.27 UK pence per test well. Aliquots of this reagent are ready to be supplied to qualified groups anywhere in the world that need to detect antibodies to SARS-CoV-2, but do not have the facilities for high throughput commercial tests.

scholarly journals AnemoCheck-LRS: an optimized, color-based point-of-care test to identify severe anemia in limited-resource settings

BMC Medicine ◽  
2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Marina S. Perez-Plazola ◽  
Erika A. Tyburski ◽  
Luke R. Smart ◽  
Thad A. Howard ◽  
Amanda Pfeiffer ◽  
...  
Keyword(s):  
Screening Tool ◽  
Point Of Care ◽  
Low Cost ◽  
Limited Resource ◽  
Absolute Difference ◽  
Severe Anemia ◽  
Detection Range ◽  
Point Of Care Test ◽  
Colour Scale ◽  
Life Saving

Abstract Background Severe anemia is common and frequently fatal for hospitalized patients in limited-resource settings. Lack of access to low-cost, accurate, and rapid diagnosis of anemia impedes the delivery of life-saving care and appropriate use of the limited blood supply. The WHO Haemoglobin Colour Scale (HCS) is a simple low-cost test but frequently inaccurate. AnemoCheck-LRS (limited-resource settings) is a rapid, inexpensive, color-based point-of-care (POC) test optimized to diagnose severe anemia. Methods Deidentified whole blood samples were diluted with plasma to create variable hemoglobin (Hb) concentrations, with most in the severe (≤ 7 g/dL) or profound (≤ 5 g/dL) anemia range. Each sample was tested with AnemoCheck-LRS and WHO HCS independently by three readers and compared to Hb measured by an electronic POC test (HemoCue 201+) and commercial hematology analyzer. Results For 570 evaluations within the limits of detection of AnemoCheck-LRS (Hb ≤ 8 g/dL), the average difference between AnemoCheck-LRS and measured Hb was 0.5 ± 0.4 g/dL. In contrast, the WHO HCS overestimated Hb with an absolute difference of 4.9 ± 1.3 g/dL for samples within its detection range (Hb 4–14 g/dL, n = 405). AnemoCheck-LRS was much more sensitive (92%) for the diagnosis of profound anemia than WHO HCS (22%). Conclusions AnemoCheck-LRS is a rapid, inexpensive, and accurate POC test for anemia. AnemoCheck-LRS is more accurate than WHO HCS for detection of low Hb levels, severe anemia that may require blood transfusion. AnemoCheck-LRS should be tested prospectively in limited-resource settings where severe anemia is common, to determine its utility as a screening tool to identify patients who may require transfusion.

scholarly journals Decreased Sensitivity of the Serological Detection of Feline Immunodeficiency Virus Infection Potentially Due to Imported Genetic Variants

Viruses ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 697 ◽  
Author(s):  
Julia Frankenfeld ◽  
Theres Meili ◽  
Marina Meli ◽  
Barbara Riond ◽  
A. Helfer-Hungerbuehler ◽  
...  
Keyword(s):  
Feline Immunodeficiency Virus ◽  
Point Of Care ◽  
Diagnostic Efficiency ◽  
Rt Pcr ◽  
Viral Loads ◽  
Feline Immunodeficiency Virus Infection ◽  
Immunodeficiency Virus ◽  
Screening Assays ◽  
Diagnostic Sensitivity And Specificity ◽  
Point Of Care Tests

Feline immunodeficiency virus (FIV) is a lentivirus of domestic cats worldwide. Diagnosis usually relies on antibody screening by point-of-care tests (POCT), e.g., by enzyme-linked immunosorbent assays (ELISA), and confirmation using Western blot (WB). We increasingly observed ELISA-negative, WB-positive samples and aimed to substantiate these observations using 1194 serum/plasma samples collected from 1998 to 2019 primarily from FIV-suspect cats. While 441 samples tested positive and 375 tested negative by ELISA and WB, 81 samples had discordant results: 70 were false ELISA-negative (WB-positive) and 11 were false ELISA-positive (WB-negative); 297 ambiguous results were not analyzed further. The diagnostic sensitivity and specificity of the ELISA (82% and 91%, respectively) were lower than those reported in 1995 (98% and 97%, respectively). The diagnostic efficiency was reduced from 97% to 86%. False ELISA-negative samples originated mainly (54%) from Switzerland (1995: 0%). Sixty-four false ELISA-negative samples were available for POCT (SNAPTM/WITNESSR): five were POCT-positive. FIV RT-PCR was positive for two of these samples and was weakly positive for two ELISA- and POCT-negative samples. Low viral loads prohibited sequencing. Our results suggest that FIV diagnosis has become more challenging, probably due to increasing travel by cats and the introduction of new FIV isolates not recognized by screening assays.

scholarly journals The QuantuMDx Q-POC SARS-CoV-2 RT-PCR assay for rapid detection of COVID-19 at point-of-care: preliminary evaluation of a novel technology

2021 ◽  
Author(s):  
Jessica Caffry ◽  
Matthew Selby ◽  
Katie Barr ◽  
George Morgan ◽  
David McGurk ◽  
...  
Keyword(s):  
Point Of Care ◽  
Reference Laboratory ◽  
Preliminary Evaluation ◽  
Rt Pcr ◽  
Reference Test ◽  
Pcr Assay ◽  
Current Standard ◽  
Primary Analysis ◽  
Point Of Care Test ◽  
Control And Management

Background: Accurate, affordable, and rapid point-of-care (PoC) diagnostics are critical to the global control and management of the COVID-19 pandemic. The current standard for accurate diagnosis of SARS-CoV-2 is laboratory-based reverse transcription polymerase chain reaction (RT-PCR). Here, we report a preliminary prospective performance evaluation of the QuantuMDx Q-POC SARS CoV-2 RT-PCR assay. Methods: Between November 2020 and March 2021, we obtained 49 longitudinal nose and throat swabs from 29 individuals hospitalised with RT-PCR confirmed COVID-19 at St Georges' NHS Foundation Trust, London (UK). In addition, we obtained 101 mid nasal swabs from healthy volunteers in June 2021. We then used these samples to evaluate the Q-POC SARS-CoV-2 RT-PCR assay. The primary analysis was to compare the sensitivity and specificity of the Q-POC test against a reference laboratory-based RT-PCR assay. Results: The overall sensitivity of the Q-POC test compared with the reference test was 96.88% (83.78%- 99.92% CI) for a cycle threshold (Ct) cut-off value for the reference test of 35 and 80.00% (64.35% to 90.95% CI) without altering the reference test's Ct cut-off value of 40. Conclusions: The Q-POC test is a sensitive, specific and rapid point-of-care test for SARS-CoV-2 at a reference Ct cut-off value of 35. The Q-POC test provides an accurate and afforda-ble option for RT-PCR at point-of-care without the need for sample pre-processing and laboratory handling. The Q-POC test would enable rapid diagnosis and clinical triage in acute care and other settings.

scholarly journals Massive Multiplexing Can Deliver a $1 Test for COVID-19

2020 ◽  
Author(s):  
Paul DN Hebert ◽  
Sean WJ Prosser ◽  
Natalia V Ivanova ◽  
Evgeny V Zakharov ◽  
Sujeevan Ratnasingham
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Rna Extraction ◽  
Respiratory Syndrome Virus ◽  
Major Advance ◽  
Rt Pcr ◽  
Screening Programs ◽  
Global Pandemic ◽  
Gene Coding ◽  
Large Scale Screening

ABSTRACTThe severe acute respiratory syndrome virus, SARS-CoV-2 (hereafter COVID-19), rapidly achieved global pandemic status, provoking large-scale screening programs in many nations. Their activation makes it imperative to identify methods that can deliver a diagnostic result at low cost. This paper describes an approach which employs sequence variation in the gene coding for its envelope protein as the basis for a scalable, inexpensive test for COVID-19. It achieves this by coupling a simple RNA extraction protocol with low-volume RT-PCR, followed by E-Gel screening and sequencing on high-throughput platforms to analyze 10,000 samples in a run. Slight modifications to the protocol could support screening programs for other known viruses and for viral discovery. Just as the $1,000 genome is transforming medicine, a $1 diagnostic test for viral and bacterial pathogens would represent a major advance for public health.

scholarly journals Highly performing point-of-care molecular testing for SARS-CoV-2 with RNA extraction and isothermal amplification.

2020 ◽  
Author(s):  
Pierre Garneret ◽  
Etienne Coz ◽  
Elian Martin ◽  
Jean-Claude Manuguerra ◽  
Elodie Brient-Litzler ◽  
...  
Keyword(s):  
Point Of Care ◽  
Low Cost ◽  
Rna Extraction ◽  
Dna Amplification ◽  
Developed Countries ◽  
Temperature Cycling ◽  
Isothermal Amplification ◽  
Nucleic Acid Amplification ◽  
Clinical Samples ◽  
Molecular Testing

In order to respond to the urgent request of massive testing, developed countries perform nucleic acid amplification tests (NAAT) of SARS-CoV-2 in centralized laboratories. Real-time RT - PCR (Reverse transcription - Polymerase Chain Reaction) is used to amplify the viral RNA and enable its detection. Although PCR is 37 years old, it is still considered, without dispute, as the gold standard. PCR is an efficient process, but the complex engineering required for automated RNA extraction and temperature cycling makes it incompatible for use in point of care settings. In the present work, by harnessing progress made in the past two decades in DNA amplification, microfluidics and membrane technologies, we succeeded to create a portable test, in which SARS-CoV-2 RNA is extracted, amplified isothermally by RT - LAMP (Loop-mediated Isothermal Amplification), and detected using intercalating dyes or highly fluorescent probes. Depending on the viral load, the detection takes between twenty minutes and one hour. Using pools of naso-pharyngal clinical samples, we estimated a sensitivity comparable to RT-qPCR (up to a Cycle threshold of 39, equivalent to <0.1 TCID50 per mL) and a 100% specificity, for other human coronaviruses and eight respiratory viruses currently circulating in Europe. We designed and fabricated an easy-to-use portable device called COVIDISC to carry out the test at the point of care. The low cost of the materials along with the absence of complex equipment paves the way towards a large dissemination of this device. The perspective of a reliable SARS-CoV-2 point of care detection, highly performing, that would deliver on-site results in less than one hour opens up a new efficient approach to manage the pandemics.

scholarly journals Rapid Isothermal Amplification and Portable Detection System for SARS-CoV-2

2020 ◽  
Author(s):  
A. Ganguli ◽  
A. Mostafa ◽  
J. Berger ◽  
M. Aydin ◽  
F. Sun ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Detection System ◽  
Point Of Care ◽  
Rna Extraction ◽  
Clinical Diagnostics ◽  
Isothermal Amplification ◽  
Sample Collection ◽  
Rt Pcr ◽  
Point Of Use ◽  
Viral Transport Medium

AbstractThe COVID-19 pandemic provides an urgent example where a gap exists between availability of state-of-the-art diagnostics and current needs. As assay details and primer sequences become widely known, many laboratories could perform diagnostic tests using methods such as RT-PCR or isothermal RT-LAMP amplification. A key advantage of RT-LAMP based approaches compared to RT-PCR is that RT-LAMP is known to be robust in detecting targets from unprocessed samples. In addition, RT-LAMP assays are performed at a constant temperature enabling speed, simplicity, and point-of-use testing. Here, we provide the details of an RT-LAMP isothermal assay for the detection of SARS-CoV-2 virus with performance comparable to currently approved tests using RT-PCR. We characterize the assay by introducing swabs in virus spiked synthetic nasal fluids, moving the swab to viral transport medium (VTM), and using a volume of that VTM for performing the amplification without an RNA extraction kit. The assay has a Limit-of-Detection (LOD) of 50 RNA copies/μL in the VTM solution within 20 minutes, and LOD of 5000 RNA copies/μL in the nasal solution. Additionally, we show the utility of this assay for real-time point-of-use testing by demonstrating detection of SARS-CoV-2 virus in less than 40 minutes using an additively manufactured cartridge and a smartphone-based reader. Finally, we explore the speed and cost advantages by comparing the required resources and workflows with RT-PCR. This work could accelerate the development and availability of SARS-CoV-2 diagnostics by proving alternatives to conventional laboratory benchtop tests.Significance StatementAn important limitation of the current assays for the detection of SARS-CoV-2 stem from their reliance on time- and labor-intensive and laboratory-based protocols for viral isolation, lysis, and removal of inhibiting materials. While RT-PCR remains the gold standard for performing clinical diagnostics to amplify the RNA sequences, there is an urgent need for alternative portable platforms that can provide rapid and accurate diagnosis, potentially at the point-of-use. Here, we present the details of an isothermal amplification-based detection of SARS-CoV-2, including the demonstration of a smartphone-based point-of-care device that can be used at the point of sample collection.

scholarly journals Host-Modulation Therapy and Chair-Side Diagnostics in the Treatment of Peri-Implantitis

Biosensors ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 44 ◽  
Author(s):  
Timo Sorsa ◽  
Joseph Bacigalupo ◽  
Mauno Könönen ◽  
Pirjo Pärnänen ◽  
Ismo T. Räisänen
Keyword(s):  
Point Of Care ◽  
Low Cost ◽  
Diagnostic Tools ◽  
Low Grade ◽  
Active Matrix ◽  
Point Of Care Test ◽  
Increased Risk ◽  
Prevention And Treatment ◽  
Potential Benefits ◽  
Low Grade Inflammation

Previous studies report periodontitis and peri-implantitis being able to induce systemic low-grade inflammation, which is known to be associated with increased risk for some systemic medical disease such as cardiovascular disease. In this regard, recent studies have shown that host modulation therapy (HMT) together with traditional mechanical and surgical treatment not only cease the progression of periodontitis but also reduce the systemic collagenolytic biomarkers in both oral fluids and circulation. This suggests that the corresponding adjunctive HMT-medication could be effective in the prevention and treatment of dental peri-implantitis, as well. Furthermore, low-cost, safe, and practical oral fluid active matrix metalloproteinase-8 (aMMP-8) lateral-flow immunotests have been proposed as point-of-care/chair-side diagnostic tools to detect peri-implantitis and periodontitis, and to monitor their effective resolutions, while using various therapeutic strategies, including host modulation. This study reports the potential benefits of HMT-medication in the prevention and treatment of dental peri-implantitis among five patients (four of five were current/ex-smokers). In addition, the aMMP-8 point-of-care test diagnosed 20 peri-implantitis and 20 healthy controls correctly. In conclusion, this study and previous studies support the potential effectiveness of HMT-medication(s) and point-of-care/chair-side technologies in the treatment and diagnostics/monitoring of peri-implantitis. However, more studies are needed to further confirm this.

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