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1.
Clin Microbiol Rev ; 34(3)2021 06 16.
Article in English | MEDLINE | ID: covidwho-1501523

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory disease coronavirus 2 (SARS-CoV-2), has led to millions of confirmed cases and deaths worldwide. Efficient diagnostic tools are in high demand, as rapid and large-scale testing plays a pivotal role in patient management and decelerating disease spread. This paper reviews current technologies used to detect SARS-CoV-2 in clinical laboratories as well as advances made for molecular, antigen-based, and immunological point-of-care testing, including recent developments in sensor and biosensor devices. The importance of the timing and type of specimen collection is discussed, along with factors such as disease prevalence, setting, and methods. Details of the mechanisms of action of the various methodologies are presented, along with their application span and known performance characteristics. Diagnostic imaging techniques and biomarkers are also covered, with an emphasis on their use for assessing COVID-19 or monitoring disease severity or complications. While the SARS-CoV-2 literature is rapidly evolving, this review highlights topics of interest that have occurred during the pandemic and the lessons learned throughout. Exploring a broad armamentarium of techniques for detecting SARS-CoV-2 will ensure continued diagnostic support for clinicians, public health, and infection prevention and control for this pandemic and provide advice for future pandemic preparedness.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19 Serological Testing/methods , COVID-19/diagnostic imaging , COVID-19/diagnosis , SARS-CoV-2/genetics , Biosensing Techniques , Genome, Viral/genetics , Humans , Nucleic Acid Amplification Techniques/methods , Point-of-Care Testing , SARS-CoV-2/immunology , Specimen Handling/methods
2.
Molecules ; 26(21)2021 Oct 31.
Article in English | MEDLINE | ID: covidwho-1488680

ABSTRACT

Early diagnosis with rapid detection of the virus plays a key role in preventing the spread of infection and in treating patients effectively. In order to address the need for a straightforward detection of SARS-CoV-2 infection and assessment of viral spread, we developed rapid, sensitive, extraction-free one-step reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and reverse transcription loop-mediated isothermal amplification (RT-LAMP) tests for detecting SARS-CoV-2 in saliva. We analyzed over 700 matched pairs of saliva and nasopharyngeal swab (NSB) specimens from asymptomatic and symptomatic individuals. Saliva, as either an oral cavity swab or passive drool, was collected in an RNA stabilization buffer. The stabilized saliva specimens were heat-treated and directly analyzed without RNA extraction. The diagnostic sensitivity of saliva-based RT-qPCR was at least 95% in individuals with subclinical infection and outperformed RT-LAMP, which had at least 70% sensitivity when compared to NSBs analyzed with a clinical RT-qPCR test. The diagnostic sensitivity for passive drool saliva was higher than that of oral cavity swab specimens (95% and 87%, respectively). A rapid, sensitive one-step extraction-free RT-qPCR test for detecting SARS-CoV-2 in passive drool saliva is operationally simple and can be easily implemented using existing testing sites, thus allowing high-throughput, rapid, and repeated testing of large populations. Furthermore, saliva testing is adequate to detect individuals in an asymptomatic screening program and can help improve voluntary screening compliance for those individuals averse to various forms of nasal collections.


Subject(s)
COVID-19/diagnosis , COVID-19/genetics , Reverse Transcriptase Polymerase Chain Reaction/methods , COVID-19 Testing/methods , Humans , Mass Screening/methods , Nucleic Acid Amplification Techniques/methods , RNA/isolation & purification , RNA, Viral/genetics , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Saliva/chemistry , Sensitivity and Specificity , Specimen Handling/methods
3.
Microbiol Spectr ; 9(2): e0073621, 2021 10 31.
Article in English | MEDLINE | ID: covidwho-1476398

ABSTRACT

The supply of testing equipment is vital in controlling the spread of SARS-CoV-2. We compared the diagnostic efficacy and tolerability of molded plastic (FinSwab; Valukumpu, Finland) versus flocked nylon (FLOQSwab; Copan, Italy) nasopharyngeal swabs in a clinical setting. Adults (n = 112) with suspected symptomatic COVID-19 infection underwent nasopharyngeal sampling with FinSwab and FLOQSwab from the same nostril at a drive-in coronavirus testing station. In a subset of 36 patients the samples were collected in a randomized order to evaluate the discomfort associated with sampling. SARS-CoV-2 and 16 other respiratory viruses, as well as human ß-actin mRNA were analyzed by using reverse transcriptase PCR (RT-PCR) assays. Among the 112 patients (mean age, 38 [standard deviation (SD), 14] years) ß-actin mRNA was found in all samples. There was no difference in the ß-actin mRNA cycle threshold (CT) values between FinSwab (mean, 22.3; SD, 3.61) and FLOQSwab (mean, 22.1; SD, 3.50; P = 0.46) swabs. There were 31 virus-positive cases (26 rhinovirus, 4 SARS-CoV-2, and 1 coronavirus-OC43), 24 of which were positive in both swabs; 3 rhinovirus positives were only found in the FinSwab, and similarly 4 rhinovirus positives were only found in the FLOQSwab. Rhinovirus CT values were similar between swab types. Of the 36 patients, 22 (61%) tolerated the sampling with the FinSwab better than with the FLOQSwab (P = 0.065). The molded plastic nasopharyngeal swab (FinSwab) was comparable to the standard flocked swab in terms of efficacy for respiratory virus detection and tolerability of sampling. IMPORTANCE We demonstrate that a molded plastic swab is a valid alternative to conventional brush-like swabs in collection of a nasopharyngeal sample for virus diagnostics.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , Nasopharynx/virology , SARS-CoV-2/isolation & purification , Specimen Handling/instrumentation , Actins/genetics , Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Plastics , RNA, Messenger/genetics , Respiratory Tract Infections/diagnosis , Rhinovirus/isolation & purification , Specimen Handling/methods , Young Adult
7.
PLoS One ; 16(9): e0257350, 2021.
Article in English | MEDLINE | ID: covidwho-1435609

ABSTRACT

SARS-CoV-2 has spread worldwide and has become a global health problem. As a result, the demand for inputs for diagnostic tests rose dramatically, as did the cost. Countries with inadequate infrastructure experience difficulties in expanding their qPCR testing capacity. Therefore, the development of sensitive and specific alternative methods is essential. This study aimed to develop, standardize, optimize, and validate conventional RT-PCR targeting the N gene of SARS-CoV-2 in naso-oropharyngeal swab samples compared to qPCR. Using bioinformatics tools, specific primers were determined, with a product expected to be 519 bp. The reaction conditions were optimized using a commercial positive control, and the detection limit was determined to be 100 fragments. To validate conventional RT-PCR, we determined a representative sampling of 346 samples from patients with suspected infection whose diagnosis was made in parallel with qPCR. A sensitivity of 92.1% and specificity of 100% were verified, with an accuracy of 95.66% and correlation coefficient of 0.913. Under current Brazilian conditions, this method generates approximately 60% savings compared to qPCR costs. Conventional RT-PCR, validated herein, showed sufficient results for the detection of SARS-CoV-2 and can be used as an alternative for epidemiological studies and interspecies correlations.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , Nose/virology , Nucleocapsid Proteins/genetics , Oropharynx/virology , Real-Time Polymerase Chain Reaction/methods , SARS-CoV-2/genetics , Adolescent , Brazil , COVID-19/virology , DNA Primers/genetics , Female , Humans , Male , Molecular Diagnostic Techniques/methods , RNA, Viral/genetics , Reference Standards , Sensitivity and Specificity , Specimen Handling/methods
8.
Virus Res ; 305: 198575, 2021 11.
Article in English | MEDLINE | ID: covidwho-1433886

ABSTRACT

Saliva is an appropriate specimen for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) diagnosis. The possibility of pooling samples of saliva, using non-invasive bibula strips for sampling, was explored employing Bovine coronavirus (BCoV) spiked saliva. In laboratory, up to 30 saliva-soaked strips were pooled in a single tube with 2 mL of medium. After quick adsorption with the medium and vortexing, the liquid was collected and tested with a quantitative molecular assay to quantify viral RNA genome copies. On testing of single and pooled strips, the difference between the median threshold cycles (Ct) value of test performed on the single positive saliva sample and the median Ct value obtained on the pool of 30 strips, was 3.21 cycles. Saliva pooling with bibula strips could allow monitoring of COVID-19 on a large scale, reducing costs for the health bodies in terms of medical material and skilled personnel. Finally, saliva sampling is noninvasive and less traumatic than nasopharyngeal swabs and can be self-collected.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , Coronavirus, Bovine/genetics , Genome, Viral , RNA, Viral/genetics , Specimen Handling/methods , COVID-19/virology , COVID-19 Nucleic Acid Testing/economics , Humans , Limit of Detection , Reagent Strips/analysis , SARS-CoV-2/genetics , Saliva/virology
9.
Molecules ; 26(18)2021 Sep 18.
Article in English | MEDLINE | ID: covidwho-1430926

ABSTRACT

Sample preparation is an essential step for nearly every type of biochemical analysis in use today. Among the most important of these analyses is the diagnosis of diseases, since their treatment may rely greatly on time and, in the case of infectious diseases, containing their spread within a population to prevent outbreaks. To address this, many different methods have been developed for use in the wide variety of settings for which they are needed. In this work, we have reviewed the literature and report on a broad range of methods that have been developed in recent years and their applications to point-of-care (POC), high-throughput screening, and low-resource and traditional clinical settings for diagnosis, including some of those that were developed in response to the coronavirus disease 2019 (COVID-19) pandemic. In addition to covering alternative approaches and improvements to traditional sample preparation techniques such as extractions and separations, techniques that have been developed with focuses on integration with smart devices, laboratory automation, and biosensors are also discussed.


Subject(s)
High-Throughput Screening Assays/methods , Specimen Handling/methods , Biosensing Techniques/methods , COVID-19 , Communicable Diseases/diagnosis , High-Throughput Screening Assays/trends , Humans , Pandemics/prevention & control , Point-of-Care Systems/trends , Point-of-Care Testing/trends , SARS-CoV-2
10.
PLoS One ; 16(9): e0256813, 2021.
Article in English | MEDLINE | ID: covidwho-1410652

ABSTRACT

There is a worldwide need for reagents to perform SARS-CoV-2 detection. Some laboratories have implemented kit-free protocols, but many others do not have the capacity to develop these and/or perform manual processing. We provide multiple workflows for SARS-CoV-2 nucleic acid detection in clinical samples by comparing several commercially available RNA extraction methods: QIAamp Viral RNA Mini Kit (QIAgen), RNAdvance Blood/Viral (Beckman) and Mag-Bind Viral DNA/RNA 96 Kit (Omega Bio-tek). We also compared One-step RT-qPCR reagents: TaqMan Fast Virus 1-Step Master Mix (FastVirus, ThermoFisher Scientific), qPCRBIO Probe 1-Step Go Lo-ROX (PCR Biosystems) and Luna® Universal Probe One-Step RT-qPCR Kit (Luna, NEB). We used primer-probes that detect viral N (EUA CDC) and RdRP. RNA extraction methods provided similar results, with Beckman performing better with our primer-probe combinations. Luna proved most sensitive although overall the three reagents did not show significant differences. N detection was more reliable than that of RdRP, particularly in samples with low viral titres. Importantly, we demonstrated that heat treatment of nasopharyngeal swabs at 70°C for 10 or 30 min, or 90°C for 10 or 30 min (both original variant and B 1.1.7) inactivated SARS-CoV-2 employing plaque assays, and had minimal impact on the sensitivity of the qPCR in clinical samples. These findings make SARS-CoV-2 testing portable in settings that do not have CL-3 facilities. In summary, we provide several testing pipelines that can be easily implemented in other laboratories and have made all our protocols and SOPs freely available at https://osf.io/uebvj/.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , Hot Temperature , RNA, Viral/genetics , SARS-CoV-2/genetics , Virus Inactivation , COVID-19/epidemiology , COVID-19/virology , Epidemics/prevention & control , Humans , Nasopharynx/virology , Reagent Kits, Diagnostic , Reproducibility of Results , Reverse Transcriptase Polymerase Chain Reaction/methods , SARS-CoV-2/physiology , Sensitivity and Specificity , Specimen Handling/methods , Workflow
11.
Sci Rep ; 11(1): 18108, 2021 09 13.
Article in English | MEDLINE | ID: covidwho-1406409

ABSTRACT

The progress of the SARS-CoV-2 pandemic requires the design of large-scale, cost-effective testing programs. Pooling samples provides a solution if the tests are sensitive enough. In this regard, the use of the gold standard, RT-qPCR, raises some concerns. Recently, droplet digital PCR (ddPCR) was shown to be 10-100 times more sensitive than RT-qPCR, making it more suitable for pooling. Furthermore, ddPCR quantifies the RNA content directly, a feature that, as we show, can be used to identify nonviable samples in pools. Cost-effective strategies require the definition of efficient deconvolution and re-testing procedures. In this paper we analyze the practical implementation of an efficient hierarchical pooling strategy for which we have recently derived the optimal, determining the best ways to proceed when there are impediments for the use of the absolute optimum or when multiple pools are tested simultaneously and there are restrictions on the throughput time. We also show how the ddPCR RNA quantification and the nested nature of the strategy can be combined to perform self-consistency tests for a better identification of infected individuals and nonviable samples. The studies are useful to those considering pool testing for the identification of infected individuals.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , Diagnostic Tests, Routine/methods , Real-Time Polymerase Chain Reaction/methods , SARS-CoV-2/genetics , Algorithms , COVID-19/epidemiology , COVID-19/virology , Communicable Diseases/diagnosis , Communicable Diseases/virology , Humans , Models, Genetic , Pandemics , RNA, Viral/genetics , Reproducibility of Results , SARS-CoV-2/physiology , Sensitivity and Specificity , Specimen Handling/methods
12.
Sci Rep ; 11(1): 17793, 2021 09 07.
Article in English | MEDLINE | ID: covidwho-1397895

ABSTRACT

The rapid identification and isolation of infected individuals remains a key strategy for controlling the spread of SARS-CoV-2. Frequent testing of populations to detect infection early in asymptomatic or presymptomatic individuals can be a powerful tool for intercepting transmission, especially when the viral prevalence is low. However, RT-PCR testing-the gold standard of SARS-CoV-2 diagnosis-is expensive, making regular testing of every individual unfeasible. Sample pooling is one approach to lowering costs. By combining samples and testing them in groups the number of tests required is reduced, substantially lowering costs. Here we report on the implementation of pooling strategies using 3-d and 4-d hypercubes to test a professional sports team in South Africa. We have shown that infected samples can be reliably detected in groups of 27 and 81, with minimal loss of assay sensitivity for samples with individual Ct values of up to 32. We report on the automation of sample pooling, using a liquid-handling robot and an automated web interface to identify positive samples. We conclude that hypercube pooling allows for the reliable RT-PCR detection of SARS-CoV-2 infection, at significantly lower costs than lateral flow antigen (LFA) tests.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , High-Throughput Screening Assays/methods , SARS-CoV-2/isolation & purification , Specimen Handling/methods , Antigens, Viral/isolation & purification , Athletes , COVID-19/blood , COVID-19/virology , COVID-19 Nucleic Acid Testing/economics , COVID-19 Serological Testing/economics , COVID-19 Serological Testing/methods , Cost Savings , High-Throughput Screening Assays/economics , Humans , RNA, Viral/isolation & purification , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Sensitivity and Specificity , South Africa , Specimen Handling/economics , Sports Medicine/economics , Sports Medicine/methods
13.
J Int AIDS Soc ; 24(9): e25801, 2021 09.
Article in English | MEDLINE | ID: covidwho-1396894

ABSTRACT

INTRODUCTION: Provider-collected swabs are an unappealing procedure for many transgender women and may have led to suboptimal rates of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) testing. Self-collection for CT/NG testing is recommended for men who have sex with men. However, the information on acceptability and clinical performance to support a recommendation for transgender women is lacking. We aimed to determine the acceptability and satisfaction towards self-collection for CT/NG testing among Thai transgender women. METHODS: Thai transgender women who attended Tangerine Clinic (a transgender-led, integrated, gender-affirming care and sexual health services clinic in Bangkok, Thailand) between May and July 2020 and had condomless sexual intercourse within the past six months were offered to collect urine and perform self-swabs of pharyngeal, rectal, and if applicable, neovaginal compartments for pooled nucleic acid amplification testing for CT/NG infections. Participants received a diagram, video and oral instructions about how to perform self-collection procedure. Those who accepted self-collection were also offered to receive provider collection to evaluate the performance between the two methods. Self-administered questionnaires were used to assess satisfaction. RESULTS: Among 216 transgender women enrolled, 142 (65.7%) accepted self-collection. All who accepted had pharyngeal, rectal and urine samples collected. Of 31 transgender women who had undergone genital surgery, 28 (90.3%) accepted neovaginal self-swab. The acceptance rate increased from 46.2% in May to 84.5% in July 2020. One participant had an invalid result. All transgender women who accepted self-collection could perform it without assistance, and 82.8% were highly satisfied with the method. None reported dissatisfaction. Due to the COVID-19 pandemic, provider collection services were discontinued early, and only eight transgender women were able to perform both methods for performance evaluation. The performance agreement was 100%. CONCLUSIONS: Thai transgender women had high acceptability and satisfaction towards self-collection for CT/NG testing. The performance was promising compared to provider collection. Our results support the implementation of self-collection to the sexually transmitted infection services, particularly during the COVID-19 pandemic where physical distancing is the new normal. A larger study is warranted to determine the performance of self-collection for CT/NG testing in each anatomical compartment and confirm the performance between self-collection and provider collection.


Subject(s)
Chlamydia Infections/diagnosis , Chlamydia trachomatis/isolation & purification , Gonorrhea/diagnosis , Neisseria gonorrhoeae/isolation & purification , Patient Acceptance of Health Care , Personal Satisfaction , Specimen Handling/methods , Transgender Persons , Adult , COVID-19 , Chlamydia Infections/epidemiology , Female , Gonorrhea/epidemiology , Humans , Male , Pandemics , SARS-CoV-2 , Self Care , Thailand/epidemiology
14.
PLoS One ; 16(9): e0256877, 2021.
Article in English | MEDLINE | ID: covidwho-1394546

ABSTRACT

In French Polynesia, the first case of SARS-CoV-2 infection was detected on March 10th, 2020, in a resident returning from France. Between March 28th and July 14th, international air traffic was interrupted and local transmission of SARS-CoV-2 was brought under control, with only 62 cases recorded. The main challenge for reopening the air border without requiring travelers to quarantine on arrival was to limit the risk of re-introducing SARS-CoV-2. Specific measures were implemented, including the obligation for all travelers to have a negative RT-PCR test for SARS-CoV-2 carried out within 3 days before departure, and to perform another RT-PCR testing 4 days after arrival. Because of limitation in available medical staff, travelers were provided a kit allowing self-collection of oral and nasal swabs. In addition to increase our testing capacity, self-collected samples from up to 10 travelers were pooled before RNA extraction and RT-PCR testing. When a pool tested positive, RNA extraction and RT-PCR were performed on each individual sample. We report here the results of COVID-19 surveillance (COV-CHECK PORINETIA) conducted between July 15th, 2020, and February 15th, 2021, in travelers using self-collection and pooling approaches. We tested 5,982 pools comprising 59,490 individual samples, and detected 273 (0.46%) travelers positive for SARS-CoV-2. A mean difference of 1.17 Ct (CI 95% 0.93-1.41) was found between positive individual samples and pools (N = 50), probably related to the volume of samples used for RNA extraction (200 µL versus 50 µL, respectively). Retrospective testing of positive samples self-collected from October 20th, 2020, using variants-specific amplification kit and spike gene sequencing, found at least 6 residents infected by the Alpha variant. Self-collection and pooling approaches allowed large-scale screening for SARS-CoV-2 using less human, material and financial resources. Moreover, this strategy allowed detecting the introduction of SARS-CoV-2 variants of concern in French Polynesia.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , Mass Screening/methods , Population Surveillance/methods , Specimen Handling/methods , Travel , COVID-19/epidemiology , COVID-19/virology , COVID-19 Testing/instrumentation , Epidemics/prevention & control , France/epidemiology , Humans , Polynesia/epidemiology , Prospective Studies , RNA, Viral/genetics , RNA, Viral/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction/methods , SARS-CoV-2/genetics , SARS-CoV-2/physiology , Specimen Handling/instrumentation
15.
J Med Microbiol ; 70(9)2021 Sep.
Article in English | MEDLINE | ID: covidwho-1393561

ABSTRACT

Introduction. Non-invasive sample collection and viral sterilizing buffers have independently enabled workflows for more widespread COVID-19 testing by reverse-transcriptase polymerase chain reaction (RT-PCR).Gap statement. The combined use of sterilizing buffers across non-invasive sample types to optimize sensitive, accessible, and biosafe sampling methods has not been directly and systematically compared.Aim. We aimed to evaluate diagnostic yield across different non-invasive samples with standard viral transport media (VTM) versus a sterilizing buffer eNAT- (Copan diagnostics Murrieta, CA) in a point-of-care diagnostic assay system.Methods. We prospectively collected 84 sets of nasal swabs, oral swabs, and saliva, from 52 COVID-19 RT-PCR-confirmed patients, and nasopharyngeal (NP) swabs from 37 patients. Nasal swabs, oral swabs, and saliva were placed in either VTM or eNAT, prior to testing with the Xpert Xpress SARS-CoV-2 (Xpert). The sensitivity of each sampling strategy was compared using a composite positive standard.Results. Swab specimens collected in eNAT showed an overall superior sensitivity compared to swabs in VTM (70 % vs 57 %, P=0.0022). Direct saliva 90.5 %, (95 % CI: 82 %, 95 %), followed by NP swabs in VTM and saliva in eNAT, was significantly more sensitive than nasal swabs in VTM (50 %, P<0.001) or eNAT (67.8 %, P=0.0012) and oral swabs in VTM (50 %, P<0.0001) or eNAT (58 %, P<0.0001). Saliva and use of eNAT buffer each increased detection of SARS-CoV-2 with the Xpert; however, no single sample matrix identified all positive cases.Conclusion. Saliva and eNAT sterilizing buffer can enhance safe and sensitive detection of COVID-19 using point-of-care GeneXpert instruments.


Subject(s)
COVID-19 Nucleic Acid Testing , Specimen Handling/methods , Adult , Aged , COVID-19/diagnosis , Containment of Biohazards , Culture Media , Female , Humans , Male , Middle Aged , Mouth/virology , Nasopharynx/virology , Nose/virology , Point-of-Care Testing , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Saliva/virology , Sensitivity and Specificity , Specimen Handling/standards
16.
Clin Microbiol Infect ; 27(9): 1212-1220, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1392213

ABSTRACT

BACKGROUND: Pool-testing strategies combine samples from multiple people and test them as a group. A pool-testing approach may shorten the screening time and increase the test rate during times of limited test availability and inadequate reporting speed. Pool testing has been effectively used for a wide variety of infectious disease screening settings. Historically, it originated from serological testing in syphilis. During the current coronavirus disease 2019 (COVID-19) pandemic, pool testing is considered across the globe to inform opening strategies and to monitor infection rates after the implementation of interventions. AIMS: This narrative review aims to provide a comprehensive overview of the global efforts to implement pool testing, specifically for COVID-19 screening. SOURCES: Data were retrieved from a detailed search for peer-reviewed articles and preprint reports using Medline/PubMed, medRxiv, Web of Science, and Google up to 21st March 2021, using search terms "pool testing", "viral", "serum", "SARS-CoV-2" and "COVID-19". CONTENT: This review summarizes the history and theory of pool testing. We identified numerous peer-reviewed articles that describe specific details and practical implementation of pool testing. Successful examples as well as limitations of pool testing, in general and specifically related to the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA and antibodies, are reviewed. While promising, significant operational, pre-analytical, logistical, and economic challenges need to be overcome to advance pool testing. IMPLICATIONS: The theory of pool testing is well understood and numerous successful examples from the past are available. Operationalization of pool testing requires sophisticated processes that can be adapted to the local medical circumstances. Special attention needs to be paid to sample collection, sample pooling, and strategies to avoid re-sampling.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , SARS-CoV-2/isolation & purification , Specimen Handling/methods , Antibodies, Viral/analysis , Diagnostic Tests, Routine , Humans , Mass Screening , RNA, Viral/genetics , Research Design , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Sensitivity and Specificity
17.
Viruses ; 13(9)2021 09 02.
Article in English | MEDLINE | ID: covidwho-1390788

ABSTRACT

3D-printed alternatives to standard flocked swabs were rapidly developed to provide a response to the unprecedented and sudden need for an exponentially growing amount of diagnostic tools to fight the COVID-19 pandemic. In light of the anticipated shortage, a hospital-based 3D-printing platform was implemented in our institution for the production of swabs for nasopharyngeal and oropharyngeal sampling based on the freely available, open-source design provided to the community by University of South Florida's Health Radiology and Northwell Health System teams as a replacement for locally used commercial swabs. Validation of our 3D-printed swabs was performed with a head-to-head diagnostic accuracy study of the 3D-printed "Northwell model" with the cobas PCR Media® swab sample kit. We observed an excellent concordance (total agreement 96.8%, Kappa 0.936) in results obtained with the 3D-printed and flocked swabs, indicating that the in-house 3D-printed swab could be used reliably in the context of a shortage of flocked swabs. To our knowledge, this is the first study to report on autonomous hospital-based production and clinical validation of 3D-printed swabs.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , COVID-19/virology , SARS-CoV-2 , COVID-19 Testing/instrumentation , Disease Management , Humans , Nasopharynx/virology , Polymerase Chain Reaction/methods , Printing, Three-Dimensional , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Specimen Handling/methods
18.
Sci Rep ; 11(1): 13592, 2021 06 30.
Article in English | MEDLINE | ID: covidwho-1387484

ABSTRACT

With global demand for SARS-CoV-2 testing ever rising, shortages in commercially available viral transport media pose a serious problem for laboratories and health care providers. For reliable diagnosis of SARS-CoV-2 and other respiratory viruses, executed by Real-time PCR, the quality of respiratory specimens, predominantly determined by transport and storage conditions, is crucial. Therefore, our aim was to explore the reliability of minimal transport media, comprising saline or the CDC recommended Viral Transport Media (HBSS VTM), for the diagnosis of SARS-CoV-2 and other respiratory viruses (influenza A, respiratory syncytial virus, adenovirus, rhinovirus and human metapneumovirus) compared to commercial products, such as the Universal Transport Media (UTM). We question the assumptions, that the choice of medium and temperature for storage and transport affect the accuracy of viral detection by RT-PCR. Both alternatives to the commercial transport medium (UTM), HBSS VTM or saline, allow adequate detection of SARS-CoV-2 and other respiratory viruses, regardless of storage temperatures up to 28 °C and storage times up to 28 days. Our study revealed the high resilience of SARS-CoV-2 and other respiratory viruses, enabling proper detection in clinical specimens even after long-time storage at high temperatures, independent of the transport medium's composition.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , Culture Media/chemistry , Preservation, Biological/methods , SARS-CoV-2/genetics , Specimen Handling/methods , Virology/methods , Cold Temperature , Humans , Laboratory Chemicals/chemistry , Reproducibility of Results , Time Factors
20.
Infect Dis Now ; 51(6): 552-555, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1385664

ABSTRACT

OBJECTIVES: SARS-CoV-2 induces a broad spectrum of clinical manifestations, which overlap with other viral infections very common in children. We aimed to describe the percentage of positive SARS-CoV-2 RT-PCR tests in symptomatic and asymptomatic ambulatory children and to determine the predictive factors for positivity. PATIENTS AND METHODS: From June 1 to July 31, 2020, we conducted a cross-sectional prospective, multicenter study (13 hospital emergency units and 59 ambulatory pediatricians) throughout France. Children under 15 years of age with a prescription of nasopharyngeal SARS-CoV-2 RT-PCR test were enrolled. RESULTS: Among the 1,553 RT-PCR tests, 22 were positive (1.4%; 95%CI [0.9; 2.1]). In both univariate and multivariate analyses, the predictive factors for positivity were age below 2 years (OR: 4.5 [1.6; 12.7]) and history of contact (OR: 12.3 [4.6; 32.8]). CONCLUSIONS: In an epidemic stage with low SARS-CoV-2 circulation, sampling of children with nonspecific symptoms and without known contact could be questioned.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , SARS-CoV-2/isolation & purification , COVID-19/epidemiology , Child , Child, Preschool , Cross-Sectional Studies , France/epidemiology , Humans , Infant , Multivariate Analysis , Nasopharynx/virology , Predictive Value of Tests , Prevalence , Prospective Studies , Specimen Handling/methods
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