Test performance study of isothermal amplification tests for the detection of Grapevine flavescence dorée phytoplasma and ‘ Candidatus Phytoplasma solani’

EPPO Bulletin ◽  
2017 ◽  
Vol 47 (1) ◽  
pp. 18-23 ◽  
Author(s):  
N. Mehle ◽  
P. Kogovšek ◽  
F. Constable ◽  
K. De Jonghe ◽  
M. Loiseau ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Somayyeh Sedaghatjoo ◽  
Monika K. Forster ◽  
Ludwig Niessen ◽  
Petr Karlovsky ◽  
Berta Killermann ◽  
...  

AbstractTilletia controversa causing dwarf bunt of wheat is a quarantine pathogen in several countries. Therefore, its specific detection is of great phytosanitary importance. Genomic regions routinely used for phylogenetic inferences lack suitable polymorphisms for the development of species-specific markers. We therefore compared 21 genomes of six Tilletia species to identify DNA regions that were unique and conserved in all T. controversa isolates and had no or limited homology to other Tilletia species. A loop-mediated isothermal amplification (LAMP) assay for T. controversa was developed based on one of these DNA regions. The specificity of the assay was verified using 223 fungal samples comprising 43 fungal species including 11 Tilletia species, in particular 39 specimens of T. controversa, 92 of T. caries and 40 of T. laevis, respectively. The assay specifically amplified genomic DNA of T. controversa from pure cultures and teliospores. Only Tilletia trabutii generated false positive signals. The detection limit of the LAMP assay was 5 pg of genomic DNA per reaction. A test performance study that included five laboratories in Germany resulted in 100% sensitivity and 97.7% specificity of the assay. Genomic regions, specific to common bunt (Tilletia caries and Tilletia laevis together) are also provided.



2021 ◽  
Author(s):  
Massimo Micocci ◽  
Peter Buckle ◽  
Gail Hayward ◽  
A. Joy Allen ◽  
Kerrie Davies ◽  
...  

AbstractIntroductionSuccessful adoption of POCTs (Point-of-Care tests) for COVID-19 in care homes requires the identification of ideal use cases and a full understanding of contextual and usability factors that affect test results and minimise biosafety risks. This paper presents findings from a scoping-usability and test performance study of a microfluidic immunofluorescence assay for COVID-19 in care homes.MethodsA mixed-methods evaluation was conducted in four UK care homes to scope usability and to assess the agreement with qRT-PCR. A dry run with luminescent dye was carried out to explore biosafety issues.ResultsThe agreement analysis was carried out on 227 asymptomatic participants (159 staff and 68 residents) and 14 symptomatic participants (5 staff and 9 residents). Asymptomatic specimens showed 50% (95% CI: 1.3%-98.7%) positive agreement and 96% (95% CI: 92.5%-98.1%) negative agreement with overall prevalence and bias-adjusted Kappa (PABAK) of 0.911 (95% CI: 0.857-0.965). Symptomatic specimens showed 83.3% (95% CI: 35.9%-99.6%) positive agreement and 100% (95% CI: 63.1%-100%) negative agreement with overall prevalence and bias-adjusted Kappa (PABAK) of 0.857 (95% CI: 0.549-1).The dry run showed four main sources of contamination that led to the modification of the standard operating procedures. Simulation after modification showed no further evidence of contamination.ConclusionCareful consideration of biosafety issues and contextual factors associated with care home are mandatory for safe use the POCT. Whilst POCT may have some utility for ruling out COVID-19, further diagnostic accuracy evaluations are needed to promote effective adoption.



EPPO Bulletin ◽  
2013 ◽  
Vol 43 (2) ◽  
pp. 267-275 ◽  
Author(s):  
R. Ioos ◽  
T. Annesi ◽  
C. Fourrier ◽  
C. Saurat ◽  
A. Chandelier ◽  
...  


2021 ◽  
pp. 251604352110542
Author(s):  
Massimo Micocci ◽  
Peter Buckle ◽  
Gail Hayward ◽  
A Joy Allen ◽  
Kerrie Davies ◽  
...  

Introduction Successful adoption of POCTs (Point-of-Care tests) for COVID-19 in care homes requires the identification of ideal use cases and a full understanding of the contextual and usability factors that affect test results and minimise biosafety risks. This paper presents a scoping-usability and test performance study of a microfluidic immunofluorescence assay for COVID-19 in care homes. Methods A mixed-methods evaluation was conducted in four UK care homes to scope usability and to assess the agreement with qRT-PCR. A dry run with luminescent dye was conducted to explore biosafety issues. Results The agreement analysis was conducted on 227 asymptomatic participants (159 staff and 68 residents) and 14 symptomatic participants (5 staff and 9 residents). Asymptomatic specimens showed 50% (95% CI:1.3%−98.7%) positive agreement and 96% (95% CI: 92.5%−98.1%) negative agreement with overall prevalence and bias-adjusted Kappa (PABAK) of 0.911 (95% CI: 0.857−0.965). Symptomatic specimens showed 83.3% (95% CI: 35.9%−99.6%) positive agreement and 100% (95% CI: 63.1%−100%) negative agreement with overall prevalence and bias-adjusted Kappa (PABAK) of 0.857 (95% CI: 0.549−1). The dry run highlighted four main sources of contamination that led to the modification of the standard operating procedures. Simulation post-modification showed no further evidence of contamination. Conclusion Careful consideration of biosafety issues and contextual factors associated with care home are mandatory for safe use the POCT. Whilst POCT may have some utility for ruling out COVID-19, further diagnostic accuracy evaluations are needed to promote effective adoption.



Anaerobe ◽  
2021 ◽  
pp. 102410
Author(s):  
Evelyne Santana Girão ◽  
Saidy Liceth Vásconez Noguera ◽  
Evelyn Patricia Sanchez Espinoza ◽  
Camila Loredana Pereira Alves Madeira Bezerra ◽  
Fernando Molina Lino ◽  
...  




2015 ◽  
Vol 144 (1) ◽  
pp. 97-108 ◽  
Author(s):  
Andrea Braun-Kiewnick ◽  
Nicole Viaene ◽  
Laurent Folcher ◽  
Fabrice Ollivier ◽  
Géraldine Anthoine ◽  
...  


Author(s):  
Sarah J Lord ◽  
Andrew St John ◽  
Patrick MM Bossuyt ◽  
Sverre Sandberg ◽  
Phillip J Monaghan ◽  
...  

Background Biomarker discovery studies often claim ‘promising’ findings, motivating further studies and marketing as medical tests. Unfortunately, the patient benefits promised are often inadequately explained to guide further evaluation, and few biomarkers have translated to improved patient care. We present a practical guide for setting minimum clinical performance specifications to strengthen clinical performance study design and interpretation. Methods We developed a step-by-step approach using test evaluation and decision-analytic frameworks and present with illustrative examples. Results We define clinical performance specifications as a set of criteria that quantify the clinical performance a new test must attain to allow better health outcomes than current practice. We classify the proposed patient benefits of a new test into three broad groups and describe how to set minimum clinical performance at the level where the potential harm of false-positive and false-negative results does not outweigh the benefits. (1) For add-on tests proposed to improve disease outcomes by improving detection, define an acceptable trade-off for false-positive versus true-positive results; (2) for triage tests proposed to reduce unnecessary tests and treatment by ruling out disease, define an acceptable risk of false-negatives as a safety threshold; (3) for replacement tests proposed to provide other benefits, or reduce costs, without compromising accuracy, use existing tests to benchmark minimum accuracy levels. Conclusions Researchers can follow these guidelines to focus their study objectives and to define statistical hypotheses and sample size requirements. This way, clinical performance studies will allow conclusions about whether test performance is sufficient for intended use.



EPPO Bulletin ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 177-185
Author(s):  
R. A. M. Vreeburg ◽  
M. Nas ◽  
B. De Paepe ◽  
T. Dreo ◽  
R. A. Gottsberger ◽  
...  


EPPO Bulletin ◽  
2015 ◽  
Vol 45 (1) ◽  
pp. 41-51 ◽  
Author(s):  
S. Loreti ◽  
N. Pucci ◽  
G. Perez ◽  
V. Catara ◽  
M. Scortichini ◽  
...  


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