Objective: When using high-throughput batched diagnostic platforms based on RT-PCR for SARS-CoV-2 detection, avoidance of the conventional nucleic acid extraction step can help to reduce the turnaround time and increase processivity. This approach can also spare reagents and plasticware, which have experienced a shortage during the initial waves of the pandemic, reducing the overall testing costs.
Methods: This study evaluated the performance of extraction-free protocols based on simple dilution of the specimen in sterile RNAse free water (with or without a heating step) in comparison to standard RNA extraction protocols, using two commercial kits for molecular detection of SARS-CoV-2 (Allplex™ SARS-CoV-2 assay and Allplex™ SARS-CoV-2/FluA/FluB/RSV assay) in nasopharyngeal swabs (NPS).
Results: Compared with conventional protocols, extraction-free protocols based on sample dilution without a heating step exhibited a lower analytical sensitivity: 74.0% and 82.1% with the Allplex™ SARS-CoV-2 assay (tested with 139 NPS samples) and the Allplex™ SARS-CoV-2/FluA/FluB/RSV assay (tested with 69 NPS samples), with a mean increase of Ct values of +2.04 and +1.32, respectively. Most false negative results were observed with sampled low viral load. Including a step of heat exposure did not improve but actually decreased the analytical sensitivity of the assay.
Conclusions: Results confirmed that extraction-free protocols could be a faster and cheaper approach to SARS-CoV-2 detection in NPS samples, which could improve processivity of diagnostic platforms.
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http://dx.doi.org/10.1016/j.ijid.2021.09.046 | DOI Listing |
J Exp Bot
December 2024
Department of Plant Pathology and Weed Research, Agricultural Research Organization - Volcani Institute, Rishon LeZion, Israel.
Acute promyelocytic leukemia (APL), distinguished by the presence of PML-RARA fusion transcript, is a medical emergency due to its high early death rate, which is preventable when diagnosed early. Current diagnostic methods are precise and reliable but are time-intensive, require sophisticated instruments and analytical expertise. This study has Redefined APL IDentification by CRISPR system (RAPID-CRISPR) to rapidly (<3hrs) detect PML-RARA.
View Article and Find Full Text PDFFront Cell Infect Microbiol
November 2024
SalivaDirect, Inc., New Haven, CT, United States.
The COVID-19 pandemic caught the world unprepared. Large-scale testing efforts were urgently needed, and diagnostic strategies had to rapidly evolve in response to unprecedented worldwide demand. However, the rollout of diagnostic testing and screening for SARS-CoV-2 was often impeded by logistical challenges, including regulatory delays, workforce shortages, laboratory bottlenecks, and supply chain disruptions.
View Article and Find Full Text PDFDiseases
August 2024
Department of Medical Laboratory Sciences, School of Biomedical and Allied Health Sciences, University of Ghana, Accra P.O. Box KB 143, Ghana.
The COVID-19 epidemic had a profound impact on global health and the economy and Ghana was no exception to its far-reaching consequences. Regarding detection of the causative agent-the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), reverse-transcription-qPCR (RT-qPCR) is widely recognized as a very sensitive and reliable diagnostic technique used globally. There are, however, high operational costs in acquiring test kits, equipment, and accessories for RT-qPCR testing, which pose significant challenges in resource-limited settings.
View Article and Find Full Text PDFMethods Mol Biol
September 2024
Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI, USA.
The use of direct nucleic acid amplification of pathogens from food matrices has the potential to reduce time to results over DNA extraction-based approaches as well as traditional culture-based approaches. Here we describe protocols for assay design and experiments for direct amplification of foodborne pathogens in food sample matrices using loop-mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR). The examples provided include the detection of Escherichia coli in milk samples and Salmonella in pork meat samples.
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