scholarly journals Evaluation of an Antigen Detection Rapid Diagnostic Test for Detection of SARS-CoV-2 in Clinical Samples

COVID ◽  
2021 ◽  
Vol 1 (4) ◽  
pp. 775-783
Author(s):  
Hoi-Ying Lam ◽  
Ka-Yi Leung ◽  
Ruiqi Zhang ◽  
Danlei Liu ◽  
Yujing Fan ◽  
...  
Keyword(s):  
Viral Load ◽  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Large Scale ◽  
Cross Reactivity ◽  
Antigen Detection ◽  
Youden Index ◽  
Clinical Samples ◽  
Analytical Sensitivity ◽  
Large Scale Screening

Antigen detection rapid diagnostic tests have been developed for first-line large-scale screening given their rapidity, simplicity, and accuracy. This study evaluates the diagnostic performance of an antigen detection rapid diagnostic test (BLOK BioScience, London, UK) detecting SARS-CoV-2 nucleocapsid protein. Serially diluted SARS-CoV-2 isolate and 110 NPS from COVID-19 patients were tested to determine the test’s sensitivity, and other viral isolates and 20 NPS from non-infected individuals were, for specificity, also tested. Ten clinical samples from COVID-19 patients with SARS-CoV-2 variants, including alpha, beta, gamma, delta, and eta variants, were collected to evaluate the test’s potential application in detecting emerging variants. Overall sensitivity was 92%, and stratifying into viral loads yielded 100% for Ct < 25 samples including SARS-CoV-2 variants, but 11.11% for Ct ≥ 30 samples. The analytical sensitivity of log10 TCID50/mL 2.0 was identified for SARS-CoV-2. Ninety-seven percent specificity with only SARS-CoV cross-reactivity lead to the Youden index of 0.89. The rapid diagnostic test has a high sensitivity for detecting SARS-CoV-2 in high viral load samples, possibly including emerging SARS-CoV-2 variants, but reduced sensitivity in low viral load samples suggests its optimized usage as a complementary testing method to other tests, including RT-PCR or a point-of-care test for large-scale screening, particularly for pandemic areas or airport border infection control.

A prospective nationwide observational study of agreement of antigen tests on oral pharyngeal swabs or less invasive testing with RT-qPCR, for detecting SARS-CoV-2 in adults: Protocol description (Preprint)

2021 ◽  
Author(s):  
Uffe Vest Schneider ◽  
Jenny Dahl Knudsen ◽  
Anders Koch ◽  
Nikolai Søren Kirkby ◽  
Jan Gorm Lisby
Keyword(s):  
Confidence Intervals ◽  
Predictive Value ◽  
Large Scale ◽  
Reference Method ◽  
Lateral Flow ◽  
Clinical Samples ◽  
Sampling Location ◽  
Analytical Sensitivity ◽  
Clinical Sensitivity ◽  
Antigen Tests

BACKGROUND The SARS-CoV-2 pandemic has resulted in an unprecedented level of world-wide testing for epidemiologic and diagnostic purposes, and due to the extreme need for tests, the gold standard reverse transcription polymerase chain reaction (RT-qPCR) testing capacity has been unable to meet the overall global testing demand. Consequently, although current literature has shown the sensitivity of rapid antigen tests (RATs) to be inferior to RT-qPCR, RATs have been implemented on a large scale without solid data on performance. OBJECTIVE This study will compare analytical and clinical sensitivities and specificities of 50 lateral flow or laboratory based RATs and three Strand Invasion Based Amplification (SIBA)-rt-PCR tests from 30 manufacturers to RT-qPCR on samples obtained from the deep oropharynx. In addition, the study will compare sensitivities and specificities of the included RATs as well as RT-qPCR on clinical samples obtained from the deep oropharynx, anterior nasal cavity, saliva, deep nasopharynx and expired air to RT-qPCR from deep oropharyngeal samples. METHODS In the prospective part of the study, 200 individuals found SARS-CoV-2 positive and 200 individuals found SARS-CoV-2 negative by routine RT-qPCR testing will be re-tested with each RAT applying RT-qPCR as the reference method. In the retrospective part of the study, 304 deep oropharyngeal cavity swabs divided into four groups based on RT-qPCR Cq levels will be tested by each RAT. RESULTS The results will be reported in several manuscripts with different aims. The first manuscript will report retrospective (analytical sensitivity, overall and stratified into different Cq range groups) and prospective (clinical sensitivity) data for RATs with RT-qPCR results as the reference method. The second manuscript will report results for RAT based on anatomical sampling location. The third manuscript will compare different anatomical sampling locations by RT-qPCR testing. The fourth manuscript will focus on RATs that rely on central laboratory testing. Test from four different manufactures will be compared for analytical performance data on retrospective deep oropharyngeal swab samples. The fifth manuscript will report the results of four RATs applied both as professional use and as self-test. The last manuscript will report the results from two breath tests participating in the study. Comparison of sensitivity and specificity between RATs will be done using McNemar for paired samples and chi-squared test for unpaired samples. Comparison of PPV and NPV between RATs will be done by bootstrap test. 95 % confidence intervals for sensitivity, specificity, positive predictive value and negative predictive value are calculated as bootstrap confidence intervals CONCLUSIONS The study will compare the sensitivities of a large number of RATs for SARS-CoV-2 compared to RT-qPCR and will address whether lateral flow based RATs test differ significantly from laboratory based RATS. The anatomical test location for both RAT and RT-qPCR will be compared. CLINICALTRIAL ClinicalTrials.gov NCT04913116

scholarly journals High-Accuracy Determination of Microsatellite Instability Compatible with Liquid Biopsies

2020 ◽  
Vol 66 (4) ◽  
pp. 606-613 ◽  
Author(s):  
Amanda Bortolini Silveira ◽  
François-Clément Bidard ◽  
Amélie Kasperek ◽  
Samia Melaabi ◽  
Marie-Laure Tanguy ◽  
...  
Keyword(s):  
Microsatellite Instability ◽  
Large Scale ◽  
Digital Pcr ◽  
Circulating Tumor Dna ◽  
Diagnostic Tools ◽  
Tumor Biomarker ◽  
Analytical Sensitivity ◽  
Liquid Biopsies ◽  
Tumor Dna ◽  
Large Scale Screening

Abstract Background Microsatellite instability (MSI) has recently emerged as a predictive pan-tumor biomarker of immunotherapy efficacy, stimulating the development of diagnostic tools compatible with large-scale screening of patients. In this context, noninvasive detection of MSI from circulating tumor DNA stands as a promising diagnostic and posttreatment monitoring tool. Methods We developed drop-off droplet-digital PCR (ddPCR) assays targeting BAT-26, activin A receptor type 2A (ACVR2A), and defensin beta 105A/B (DEFB105A/B) microsatellite markers. Performances of the assays were measured on reconstitution experiments of various mutant allelic fractions, on 185 tumor samples with known MSI status, and on 72 blood samples collected from 42 patients with advanced colorectal or endometrial cancers before and/or during therapy. Results The 3 ddPCR assays reached analytical sensitivity &lt;0.1% variant allelic frequency and could reliably detect and quantify MSI in both tumor and body fluid samples. High concordance between MSI status determination by the three-marker ddPCR test and the reference pentaplex method were observed (100% for colorectal tumors and 93% for other tumor types). Moreover, the 3 assays showed correlations with r ≥ 0.99 with other circulating tumor DNA markers and their dynamic during treatment correlated well with clinical response. Conclusions This innovative approach for MSI detection provides a noninvasive, cost-effective, and fast diagnostic tool, well suited for large-scale screening of patients that may benefit from immunotherapy agents, as well as for monitoring treatment responses.

scholarly journals Performance Evaluation of Commercial Dengue Diagnostic Tests for Early Detection of Dengue in Clinical Samples

2017 ◽  
Vol 2017 ◽  
pp. 1-4 ◽  
Author(s):  
Tuan Nur Akmalina Mat Jusoh ◽  
Rafidah Hanim Shueb
Keyword(s):  
Dengue Virus ◽  
Real Time ◽  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Dengue Infection ◽  
Clinical Samples ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rt Pcr ◽  
Serum Samples ◽  
Kappa Agreement

The shattering rise in dengue virus infections globally has created a need for an accurate and validated rapid diagnostic test for this virus. Rapid diagnostic test (RDT) and reverse transcription-polymerase chain reaction (RT-PCR) diagnostic detection are useful tools for diagnosis of early dengue infection. We prospectively evaluated the diagnostic performance of nonstructural 1 (NS1) RDT and real-time RT-PCR diagnostic kits in 86 patient serum samples. Thirty-six samples were positive for dengue NS1 antigen while the remaining 50 were negative when tested with enzyme-linked immunosorbent assay (ELISA). Commercially available RDTs for NS1 detection, RTK ProDetect™, and SD Bioline showed high sensitivity of 94% and 89%, respectively, compared with ELISA. GenoAmp® Trioplex Real-Time RT-PCR and RealStar® Dengue RT-PCR tests presented a comparable kappa agreement with 0.722. The result obtained from GenoAmp® Real-Time RT-PCR Dengue test showed that 14 samples harbored dengue virus type 1 (DENV-1), 8 samples harbored DENV-2, 2 samples harbored DENV-3, and 1 sample harbored DENV-4. 1 sample had a double infection with DENV-1 and DENV-2. The NS1 RDTs and real-time RT-PCR tests were found to be a useful diagnostic for early and rapid diagnosis of acute dengue and an excellent surveillance tool in our battle against dengue.

scholarly journals SARS-CoV-2 antigen rapid diagnostic test enhanced with silver amplification technology

2021 ◽  
Author(s):  
Kei Miyakawa ◽  
Rikako Funabashi ◽  
Yutaro Yamaoka ◽  
Sundararaj Stanleyraj Jeremiah ◽  
Junichi Katada ◽  
...  
Keyword(s):  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Point Of Care ◽  
Rapid Diagnosis ◽  
Clinical Samples ◽  
Nasopharyngeal Swab ◽  
Special Equipment ◽  
Viral Spread ◽  
Silver Amplification ◽  
Low Sensitivity

AbstractRapid diagnosis of COVID-19 is essential for instituting measures to prevent viral spread. SARS-CoV-2 antigen rapid diagnostic test (Ag-RDT) based on lateral flow immunochromatography assay (LFIA) principle can visually indicate the presence of SARS-CoV-2 antigens as a band. Ag-RDT is clinically promising as a point-of-care testing because it can give results in a short time without the need for special equipment. Although various antigen capture LFIAs are now available for rapid diagnosis for SARS-CoV-2 infection, they face the problems of low sensitivity. We have previously developed highly specific monoclonal antibodies (mAb) against SARS-CoV-2 nucleocapsid protein (NP) and in this study, we have employed these mAbs to develop a new LFIA that can detect SARS-CoV-2 NP in nasopharyngeal swab samples with higher sensitivity by combining them with silver amplification technology. We also compared the performance of our Ag-RDT against the commercially available Ag-RDTs using clinical samples to find that our newly developed LFIA performed best among tested, highlighting the superiority of silver amplification technology.

Viral load and rapid diagnostic test in patients with pandemic H1N1 2009

2011 ◽  
Vol 53 (6) ◽  
pp. 1097-1099 ◽  
Author(s):  
Masahiro Watanabe ◽  
Souichi Nukuzuma ◽  
Masahiro Ito ◽  
Toshiaki Ihara
Keyword(s):  
Viral Load ◽  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Pandemic H1n1 ◽  
Pandemic H1n1 2009

Large-scale evaluation of a rapid diagnostic test for human cystic echinococcosis

2017 ◽  
Vol 89 (1) ◽  
pp. 20-25 ◽  
Author(s):  
Alice Baraquin ◽  
Houria Zait ◽  
Florence-Elisabeth Grenouillet ◽  
Elise Moreau ◽  
Boussad Hamrioui ◽  
...  
Keyword(s):  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Cystic Echinococcosis ◽  
Large Scale ◽  
Scale Evaluation ◽  
Human Cystic Echinococcosis

scholarly journals Imported Malaria confirmed by immuno-assay

QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
S S Abdelgawad ◽  
E Y Abusarea ◽  
R M Shaapan ◽  
M A Ghieth
Keyword(s):  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Parasitic Infection ◽  
Blood Film ◽  
Antigen Detection ◽  
Imported Malaria ◽  
Confirmatory Test ◽  
Endemic Region ◽  
Malaria Antigen ◽  
Kappa Agreement

Abstract Background Malaria is the most clinically critical parasitic infection worldwide with undesirable morbidity and mortality. Aim of the Study This study detected the efficacy of rapid diagnostic test for detection of imported malaria among patients with history of fever and/or had travelled to malaria endemic region. Subjects and Methods Blood samples were collected through a year from 732 patients attending three medical laboratories at El Wasta city, Beni-Suef, Egypt. Malaria was tested using thin and thick Geimsa stained blood film and rapid diagnostic test (RDTs) for immunological detection of malaria antigen. Results Microscopy reveled malaria in 4 samples (0.5%) distributed as follow, P. vivax, P. falciparum, mixed P. falciparum and P. vivax infection (0.5%, 0.25%, 0.25%, respectively). Antigen detection was positive in 7 cases (0.9%) with maximum sensitivity, satisfied specificity (100%, 98.5%, respectively) and substantial Kappa agreement (0.677). All positive samples for malaria by microscopy were confirmed by malaria antigen detection. All positive samples by microscopy and/or immune-assay were traveled to Sudan (71.4%) or Yemen (28.6%). Conclusion Sudan is considered a major focus for imported malaria in Egypt, much restriction rules are needed for travellers and immigrants. Antigen detection using RDTs is a satisfied confirmatory test for suspected cases with fever history.

scholarly journals OmniSARS2: A Highly Sensitive and Specific RT-qPCR-Based COVID-19 Diagnostic Method Designed to Withstand SARS-CoV-2 Lineage Evolution

Biomedicines ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1314
Author(s):  
Eduarda Carvalho-Correia ◽  
Carla Calçada ◽  
Fernando Branca ◽  
Nuria Estévez-Gómez ◽  
Loretta De Chiara ◽  
...  
Keyword(s):  
Cross Reactivity ◽  
Diagnostic Methods ◽  
Molecular Diagnostic ◽  
Clinical Samples ◽  
Analytical Sensitivity ◽  
S Gene ◽  
Genomic Knowledge ◽  
Gene Assay ◽  
One Step

Extensive transmission of SARS-CoV-2 during the COVID-19 pandemic allowed the generation of thousands of mutations within its genome. While several of these become rare, others largely increase in prevalence, potentially jeopardizing the sensitivity of PCR-based diagnostics. Taking advantage of SARS-CoV-2 genomic knowledge, we designed a one-step probe-based multiplex RT-qPCR (OmniSARS2) to simultaneously detect short fragments of the SARS-CoV-2 genome in ORF1ab, E gene and S gene. Comparative genomics of the most common SARS-CoV-2 lineages, other human betacoronavirus and alphacoronavirus, was the basis for this design, targeting both highly conserved regions across SARS-CoV-2 lineages and variable or absent in other Coronaviridae viruses. The highest analytical sensitivity of this method for SARS-CoV-2 detection was 94.2 copies/mL at 95% detection probability (~1 copy per total reaction volume) for the S gene assay, matching the most sensitive available methods. In vitro specificity tests, performed using reference strains, showed no cross-reactivity with other human coronavirus or common pathogens. The method was compared with commercially available methods and detected the virus in clinical samples encompassing different SARS-CoV-2 lineages, including B.1, B.1.1, B.1.177 or B.1.1.7 and rarer lineages. OmniSARS2 revealed a sensitive and specific viral detection method that is less likely to be affected by lineage evolution oligonucleotide–sample mismatch, of relevance to ensure the accuracy of COVID-19 molecular diagnostic methods.

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