Abstract
Objectives
To establish the optimal parameters for group testing of pooled specimens for the detection of SARS-CoV-2.
Methods
The most efficient pool size was determined to be five specimens ...using a web-based application. From this analysis, 25 experimental pools were created using 50 µL from one SARS-CoV-2 positive nasopharyngeal specimen mixed with 4 negative patient specimens (50 µL each) for a total volume of 250 µL. Viral RNA was subsequently extracted from each pool and tested using the CDC SARS-CoV-2 RT-PCR assay. Positive pools were consequently split into individual specimens and tested by extraction and PCR. This method was also tested on an unselected group of 60 nasopharyngeal specimens grouped into 12 pools.
Results
All 25 pools were positive with cycle threshold (Ct) values within 0 and 5.03 Ct of the original individual specimens. The analysis of 60 specimens determined that 2 pools were positive followed by identification of 2 individual specimens among the 60 tested. This testing was accomplished while using 22 extractions/PCR tests, a savings of 38 reactions.
Conclusions
When the incidence rate of SARS-CoV-2 infection is 10% or less, group testing will result in the saving of reagents and personnel time with an overall increase in testing capability of at least 69%.
How to Obtain a Nasopharyngeal Swab Specimen Marty, Francisco M; Chen, Kaiwen; Verrill, Kelly A
The New England journal of medicine,
05/2020, Letnik:
382, Številka:
22
Journal Article
The expense of saliva collection devices designed to stabilize severe acute respiratory syndrome coronavirus 2 RNA is prohibitive to mass testing. However, virus RNA in nonsupplemented saliva is ...stable for extended periods and at elevated temperatures. Simple plastic tubes for saliva collection will make large-scale testing and continued surveillance easier.
A novel zoonotic coronavirus outbreak is spreading all over the world. This pandemic disease has now been defined as novel coronavirus disease 2019 (COVID-19), and is sustained by severe acute ...respiratory syndrome coronavirus 2 (SARS-CoV-2). As the current gold standard for the etiological diagnosis of SARS-CoV-2 infection is (real time) reverse transcription polymerase chain reaction (rRT-PCR) on respiratory tract specimens, the diagnostic accuracy of this technique shall be considered a foremost prerequisite. Overall, potential RT-PCR vulnerabilities include general preanalytical issues such as identification problems, inadequate procedures for collection, handling, transport and storage of the swabs, collection of inappropriate or inadequate material (for quality or volume), presence of interfering substances, manual errors, as well as specific aspects such as sample contamination and testing patients receiving antiretroviral therapy. Some analytical problems may also contribute to jeopardize the diagnostic accuracy, including testing outside the diagnostic window, active viral recombination, use of inadequately validated assays, insufficient harmonization, instrument malfunctioning, along with other specific technical issues. Some practical indications can hence be identified for minimizing the risk of diagnostic errors, encompassing the improvement of diagnostic accuracy by combining clinical evidence with results of chest computed tomography (CT) and RT-PCR, interpretation of RT-PCR results according to epidemiologic, clinical and radiological factors, recollection and testing of upper (or lower) respiratory specimens in patients with negative RT-PCR test results and high suspicion or probability of infection, dissemination of clear instructions for specimen (especially swab) collection, management and storage, together with refinement of molecular target(s) and thorough compliance with analytical procedures, including quality assurance.
The term “biobanking” is often misapplied to any collection of human biological materials (biospecimens) regardless of requirements related to ethical and legal issues or the standardization of ...different processes involved in tissue collection. A proper definition of biobanks is large collections of biospecimens linked to relevant personal and health information (health records, family history, lifestyle, genetic information) that are held predominantly for use in health and medical research. In addition, the International Organization for Standardization, in illustrating the requirements for biobanking (ISO 20387:2018), stresses the concept of biobanks being legal entities driving the process of acquisition and storage together with some or all of the activities related to collection, preparation, preservation, testing, analysing and distributing defined biological material as well as related information and data. In this review article, we aim to discuss the basic principles of biobanking, spanning from definitions to classification systems, standardization processes and documents, sustainability and ethical and legal requirements. We also deal with emerging specimens that are currently being generated and shaping the so-called next-generation biobanking, and we provide pragmatic examples of cancer-associated biobanking by discussing the process behind the construction of a biobank and the infrastructures supporting the implementation of biobanking in scientific research.
Diagnosis and surveillance of Barrett's esophagus (BE) and eosinophilic esophagitis (EoE) have become emerging public health issues. Cytosponge is a novel, minimally invasive esophageal cell ...collection device. We aimed to assess the data on safety and acceptability of this device.
We performed a patient-level review of 5 prospective trials assessing Cytosponge performance in patients with reflux disease, BE and EoE in primary and secondary care. Acceptability of Cytosponge and subsequent endoscopy were recorded with visual analogue scale (VAS), wherein 0 and 10 denoted lowest and highest acceptability. Median VAS scores were compared using a Mann-Whitney test. The number of attempts, failures in swallowing the device and occurrence of adverse events were analyzed. Risk factors for failure in swallowing were analyzed using a multivariate regression model.
In total, 2672 Cytosponge procedures were performed, in 2418 individuals from 2008 through 2017. There were 2 adverse events related to the device: a minor pharyngeal bleed and a case of detachment (<1:2000). The median acceptability score for the Cytosponge was 6.0 (interquartile range IQR, 5.0-8.0), which was higher than the score for endoscopy without sedation (median 5.0; IQR, 3.0-7.0; P < .001) and lower than the score for endoscopy with sedation (median 8.0; IQR, 5.0-9.0; P < .001). Nearly all patients (91.1%) successfully swallowed the Cytosponge, most on the first attempt (90.1%). Failure to swallow the device was more likely to occur in secondary care (odds ratio, 5.13; 95% CI, 1.48-17.79; P < .01).
The Cytosponge test is a safe procedure with good acceptability ratings in a variety of health care settings.
Highlights • Obtaining meaningful data of the CAR requires attention to methodological detail. • The ISPNE initiated an expert panel to establish quality standards of CAR assessment. • The results of ...this initiative are summarized. • Detailed methodological considerations are outlined and discussed. • Agreed consensus guidelines are presented.
The goals of the Earth Biogenome Project-to sequence the genomes of all eukaryotic life on earth-are as daunting as they are ambitious. The Darwin Tree of Life Project was founded to demonstrate the ...credibility of these goals and to deliver at-scale genome sequences of unprecedented quality for a biogeographic region: the archipelago of islands that constitute Britain and Ireland. The Darwin Tree of Life Project is a collaboration between biodiversity organizations (museums, botanical gardens, and biodiversity institutes) and genomics institutes. Together, we have built a workflow that collects specimens from the field, robustly identifies them, performs sequencing, generates high-quality, curated assemblies, and releases these openly for the global community to use to build future science and conservation efforts.
Dried blood spot (DBS) analysis has been introduced more and more into clinical practice to facilitate Therapeutic Drug Monitoring (TDM). To assure the quality of bioanalytical methods, the design, ...development and validation needs to fit the intended use. Current validation requirements, described in guidelines for traditional matrices (blood, plasma, serum), do not cover all necessary aspects of method development, analytical- and clinical validation of DBS assays for TDM. Therefore, this guideline provides parameters required for the validation of quantitative determination of small molecule drugs in DBS using chromatographic methods, and to provide advice on how these can be assessed. In addition, guidance is given on the application of validated methods in a routine context. First, considerations for the method development stage are described covering sample collection procedure, type of filter paper and punch size, sample volume, drying and storage, internal standard incorporation, type of blood used, sample preparation and prevalidation. Second, common parameters regarding analytical validation are described in context of DBS analysis with the addition of DBS-specific parameters, such as volume-, volcano- and hematocrit effects. Third, clinical validation studies are described, including number of clinical samples and patients, comparison of DBS with venous blood, statistical methods and interpretation, spot quality, sampling procedure, duplicates, outliers, automated analysis methods and quality control programs. Lastly, cross-validation is discussed, covering changes made to existing sampling- and analysis methods. This guideline of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology on the development, validation and evaluation of DBS-based methods for the purpose of TDM aims to contribute to high-quality micro sampling methods used in clinical practice.
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