scholarly journals Evaluation of the Advanta Dx SARS-CoV-2 RT-PCR Assay, a High-Throughput Extraction-Free Diagnostic Test for the Detection of SARS-CoV-2 in Saliva: A Diagnostic Accuracy Study

Diagnostics ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1766
Author(s):  
Sofia Balaska ◽  
Dimitrios Pilalas ◽  
Anna Takardaki ◽  
Paraskevoula Koutra ◽  
Eleftheria Parasidou ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Healthcare Workers ◽  
Reference Method ◽  
Nasopharyngeal Swab ◽  
Molecular Testing ◽  
Rt Pcr ◽  
Convenience Sample ◽  
Accuracy Study ◽  
Diagnostic Samples ◽  
Saliva Test

Nasopharyngeal swab specimen (NPS) molecular testing is considered the gold standard for SARS-CoV-2 detection. However, saliva is an attractive, noninvasive specimen alternative. The aim of the study was to evaluate the diagnostic accuracy of Advanta Dx SARS-CoV-2 RT-PCR saliva-based assay against paired NPS tested with either NeumoDxTM SARS-CoV-2 assay or Abbott Real Time SARS-CoV-2 assay as the reference method. We prospectively evaluated the method in two settings: a diagnostic outpatient and a healthcare worker screening convenience sample, collected in November–December 2020. SARS-CoV-2 was detected in 27.7% (61/220) of diagnostic samples and in 5% (10/200) of screening samples. Overall, saliva test in diagnostic samples had a sensitivity of 88.5% (77.8–95.3%) and specificity of 98.1% (94.6–99.6%); in screening samples, the sensitivity was 90% (55.5–99.7%) and specificity 100% (98.1–100%). Our data suggests that the Fluidigm Advanta Dx RT-PCR saliva-based assay may be a reliable diagnostic tool for COVID-19 diagnosis in symptomatic individuals and screening asymptomatic healthcare workers.

scholarly journals Validation of the Panbio™ COVID-19 Antigen Rapid Test (Abbott) to screen for SARS-CoV-2 infection in Sint Maarten: a diagnostic accuracy study

2021 ◽  
Author(s):  
Colin King ◽  
Eva Lista-de Weever ◽  
Maria Henry ◽  
Radjin Steingrover ◽  
Chérina Fleming ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Close Contact ◽  
Rapid Test ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
The Public ◽  
Negative Results ◽  
Accuracy Study ◽  
Antigen Tests ◽  
Dutch Caribbean

AbstractObjectivesControl of the pandemic has required countries to look for other forms of tests besides the gold standard real-time polymerase chain reaction (RT-PCR). Rapid antigen tests (RAT), though less sensitive than RT-PCR, offer the possibility of rapid, inexpensive and early detection of the most infectious COVID-19 cases. Only very few studies have assessed the performance of the Abbott Panbio COVID-19 RAT among asymptomatic people or in Latin America. This study set out to validate this test among people attending the public test street in Sint Maarten, Dutch Caribbean.MethodsPeople of all ages were recruited from the public COVID-19 test street regardless of COVID-19 symptoms. They received a nasopharyngeal swab for the Abbott Panbio COVID-19 RAT and the RT-PCR Qtower. Diagnostic accuracy of the RAT was compared to the RT-PCR among the overall study population and for subgroups with/without symptoms, with/without close contact and different Ct values.ResultsUsing a RT-PCR Ct cut-off value of <33, 119 out of 1,411 people (8.4%) tested positive for SARS-CoV-2. Most were asymptomatic (59%). The overall sensitivity and specificity of the RAT was 84% (95% CI 76.2-90.1) and 99.9% (95% CI 99.6-100) respectively. The sensitivity reduced to 67.6% (95% CI: 49.5%, 82.6%) among people without symptoms, regardless of whether they were in close contact with a known COVID-19 case. Sensitivity reduced considerably with a Ct cut-off value of <35.ConclusionsThe Abbott Panbio RAT is a valid and cheaper alternative to RT-PCR when used on symptomatic individuals among the general population. However, among asymptomatic people it should not be used as a stand-alone test and negative results should be confirmed with RT-PCR.

scholarly journals Anterior nasal versus nasal mid-turbinate sampling for a SARS-CoV-2 antigen-detecting rapid test: does localisation or professional collection matter?

2021 ◽  
Author(s):  
Olga Nikolai ◽  
Chiara Rohardt ◽  
Frank Tobian ◽  
Andrea Junge ◽  
Victor M. Corman ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Rapid Test ◽  
Nasopharyngeal Swab ◽  
Diagnostic Accuracy Study ◽  
Rt Pcr ◽  
Percent Agreement ◽  
Accuracy Study ◽  
Polymerase Chain ◽  
Sensitivity Specificity ◽  
Antigen Testing

AbstractObjectivesThe aim of this diagnostic accuracy study was direct comparison of two different nasal sampling methods for an antigen-based rapid diagnostic test (Ag-RDT) that detects severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Furthermore, the accuracy and feasibility of self-sampling was evaluated.MethodsThis manufacturer-independent, prospective diagnostic accuracy study, compared professional anterior nasal (AN) and nasal mid-turbinate (NMT) sampling for a WHO-listed SARS-CoV-2 Ag-RDT. A second group of participants collected a NMT sample themselves and underwent a professional nasopharyngeal swab for comparison. The reference standard was real-time polymerase chain reaction (RT-PCR) using combined oro-/nasopharyngeal sampling. Individuals with high suspicion of SARS-CoV-2 infection were tested. Sensitivity, specificity, and percent agreement were calculated. Self-sampling was observed without intervention. Feasibility was evaluated by observer and participant questionnaires.ResultsAmong 132 symptomatic adults, both professional AN- and NMT-sampling yielded a sensitivity of 86.1% (31/36 RT-PCR positives detected; 95%CI: 71.3-93.9) and a specificity of 100.0% (95%CI: 95.7-100). The positive percent agreement (PPA) was 100% (95%CI: 89.0-100). Among 96 additional adults, self NMT- and professional NP-sampling yielded an identical sensitivity of 91.2% (31/34; 95%CI 77.0-97.0). Specificity was 98.4% (95%CI: 91.4-99.9) with NMT- and 100.0% (95%CI: 94.2-100) with NP-sampling. The PPA was 96.8% (95%CI: 83.8-99.8). Most participants (85.3%) considered self-sampling as easy to perform.ConclusionProfessional AN- and NMT-sampling are of equivalent accuracy for an Ag-RDT in ambulatory symptomatic adults. Participants were able to reliably perform the NMT-sampling themselves, following written and illustrated instructions. Nasal self-sampling will likely facilitate scaling of SARS-CoV-2 antigen testing.

scholarly journals The management of surgical patients in the emergency setting during COVID-19 pandemic: the WSES position paper

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Belinda De Simone ◽  
Elie Chouillard ◽  
Massimo Sartelli ◽  
Walter L. Biffl ◽  
Salomone Di Saverio ◽  
...  
Keyword(s):  
Systematic Review ◽  
Emergency Surgery ◽  
Healthcare Workers ◽  
Mass Casualty ◽  
Position Paper ◽  
Surgical Patients ◽  
Nasopharyngeal Swab ◽  
Emergency Setting ◽  
Open Approach ◽  
Rt Pcr

Abstract Background Since the COVID-19 pandemic has occurred, nations showed their unpreparedness to deal with a mass casualty incident of this proportion and severity, which resulted in a tremendous number of deaths even among healthcare workers. The World Society of Emergency Surgery conceived this position paper with the purpose of providing evidence-based recommendations for the management of emergency surgical patients under COVID-19 pandemic for the safety of the patient and healthcare workers. Method A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P) through the MEDLINE (PubMed), Embase and SCOPUS databases. Synthesis of evidence, statements and recommendations were developed in accordance with the GRADE methodology. Results Given the limitation of the evidence, the current document represents an effort to join selected high-quality articles and experts’ opinion. Conclusions The aim of this position paper is to provide an exhaustive guidelines to perform emergency surgery in a safe and protected environment for surgical patients and for healthcare workers under COVID-19 and to offer the best management of COVID-19 patients needing for an emergency surgical treatment. We recommend screening for COVID-19 infection at the emergency department all acute surgical patients who are waiting for hospital admission and urgent surgery. The screening work-up provides a RT-PCR nasopharyngeal swab test and a baseline (non-contrast) chest CT or a chest X-ray or a lungs US, depending on skills and availability. If the COVID-19 screening is not completed we recommend keeping the patient in isolation until RT-PCR swab test result is not available, and to manage him/she such as an overt COVID patient. The management of COVID-19 surgical patients is multidisciplinary. If an immediate surgical procedure is mandatory, whether laparoscopic or via open approach, we recommend doing every effort to protect the operating room staff for the safety of the patient.

scholarly journals COVID-19 serological testing for Healthcare Workers in Lombardy, Italy

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
G Del Castillo ◽  
A Castrofino ◽  
F Grosso ◽  
A Barone ◽  
L Crottogini ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Geographical Area ◽  
Healthcare Facility ◽  
Nasopharyngeal Swab ◽  
Infection Prevalence ◽  
Serological Testing ◽  
Prevention Policy ◽  
Rt Pcr ◽  
Serological Tests ◽  
Screening Process

Abstract Issue COVID-19 pandemic began in Italy on February 20th, 2020. Since the beginning of the emergency Healthcare Workers' (HCWs) involvement was prominent, mainly due to direct assistance to COVID-19 patients. Therefore, we implemented a prevention policy for HCW screening through serological and RT-PCR testing. Description of the problem HCW screening for SARS-CoV-2 infection is essential for prevention and control of the pandemic. Lombardy's Healthcare authorities settled a screening process for HCWs divided into three steps: 1) body temperature assessment at the beginning and the end of work shift, if fever &gt; 37.5 °C was present the HCW was sent back home and a nasopharyngeal swab was performed; 2) progressive recruitment for serological testing; 3) on those positive to IgG a nasopharyngeal swab was performed and tested for viral RNA by RT-PCR. Results Among 79185 HCW tested, 9589 (12%) were positive on serological IgG testing. Of the 9589 positive a nasopharyngeal swab was performed on 6884. Of these 358 (5%) tested positive and the remaining 6526 (95%) negative to RT-PCR. We calculated a Positive Predictive Value of 5.2%. The rate of positive serological tests for each Healthcare facility varied between 0% and 78%. Five percent of all facilities, belonging to Brescia, Bergamo and Cremona area, reported a positivity rate higher than 40% in HCWs. A second cluster (18% of all facilities), involving the same geographical area, reported a rate between 20% and 40%, whereas the remaining facilities (76%) of the region a rate &lt;20%. Lessons Serological IgG testing can be, if followed by immediate nasopharyngeal swab testing, a valid screening intervention on asymptomatic HCWs especially in a high infection prevalence setting. Key messages Serological IgG testing can be, if followed by immediate nasopharyngeal swab testing, a valid screening intervention on asymptomatic HCWs. Infection prevention in HCW may benefit from a screening campaign especially in high prevalence settings.

scholarly journals Response to BNT162b2 mRNA COVID-19 vaccine among healthcare workers in Italy: a 3-month follow-up

2021 ◽  
Author(s):  
Domenico Ponticelli ◽  
Fabiana Madotto ◽  
Sara Conti ◽  
Ippazio C. Antonazzo ◽  
Andrea Vitale ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Future Research ◽  
Nasopharyngeal Swab ◽  
Special Focus ◽  
Rt Pcr ◽  
Vaccine Response ◽  
Serology Testing ◽  
Effectiveness Data

AbstractThis study investigated the response to BNT162b2 mRNA COVID-19 vaccine among healthcare workers (HCWs) in an Italian teaching hospital. 444 participants were surveyed with either multiple RT-PCR assays for detection of SARS-CoV-2 nucleic acid in nasopharyngeal swabs or serology testing for the research of virus-specific immunoglobulins. Adverse events following immunization (AEFI) were reported. Two weeks after the first dose anti-SARS-CoV-2 antibodies exceeded reactivity cut-off in 82.5% the participants. Four HCWs tested positive at nasopharyngeal swab after 3 months. More than three-quarters reported AEFIs. Our findings offer an insight regarding the vaccine response after 3 months from its administration, with a special focus on effectiveness data, as well as the type and number of AEFIs complained by HCW recipients. The presented study may serve as reference for future research which will be necessary to explore the long-term safety of this vaccine, especially in population at high risk for infection, such as HCWs.

scholarly journals A multi-laboratory comparison of two molecular methods for the detection of toxigenic Clostridium difficile

2016 ◽  
Vol 10 (01) ◽  
pp. 62-67 ◽  
Author(s):  
Diane C Halstead ◽  
Joan Abid ◽  
Lynne Sloan ◽  
Diana Meza ◽  
Daphne Ramsey-Walker ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Molecular Characterization ◽  
Regulatory Gene ◽  
Reference Method ◽  
Molecular Methods ◽  
Detection Methods ◽  
Molecular Testing ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Toxigenic Culture

Introduction: Diarrheal disease due to toxigenic Clostridium difficile (CD) accounts for an increased number of hospitalizations and deaths each year. Published guidelines recommend reflex testing of CD antigen-positive samples to molecular testing or testing samples directly by a molecular assay. This multicenter study was designed to compare the accuracy of two different molecular methods targeting different CD genes: Xpert C. difficile Epi RUO RT-PCR assay (XPCR) which targets toxin B (Cepheid, Sunnyvale, CA) and a laboratory-developed PCR (LDPCR) which targets mutations in the tcdC regulatory gene. Methodology: Two molecular methods for toxigenic CD detection, the Xpert C. difficile Epi RUO RT-PCR assay (XPCR) [Cepheid, Sunnyvale, CA] and a laboratory-developed PCR assay (LDPCR) were compared to a consensus gold standard (CGS) or toxigenic culture (TC) as the reference method. A subset of specimens was subjected to additional molecular characterization of toxigenic CD. Results: Both molecular methods were >90% sensitive for CD detection. Discordant results were noted when molecular test results were compared to non-molecular methods. Supplemental molecular characterization illustrated inherent difficulties in comparisons using different molecular methods for CD. Conclusion: Laboratories may consider using multiple CD detection methods or combinations of methods, including molecular detection for rapid and accurate diagnosis of CD, as driven by best practices for the respective healthcare environment. Laboratories must be aware of intrinsic differences when comparing performance characteristics of different molecular assays.

scholarly journals High Resolution CHEST CT(HRCT) Evaluation in Patients Hospitalized with COVID-19 Infection

2020 ◽  
Author(s):  
Maulin Patel ◽  
Junad Chowdhury ◽  
Matthew Zheng ◽  
Osheen Abramian ◽  
Steven Verga ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
High Resolution ◽  
Diagnostic Accuracy ◽  
Reverse Transcriptase ◽  
Retrospective Analysis ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Bottom Line ◽  
Polymerase Chain

AbstractIntroductionCurrently the main diagnostic modality for COVID-19 (Coronavirus disease-2019) is reverse transcriptase polymerase chain reaction (RT-PCR) via nasopharyngeal swab which has high false negative rates. We evaluated the performance of high-resolution computed tomography (HRCT) imaging in the diagnosis of suspected COVID-19 infection compared to RT-PCR nasopharyngeal swab alone in patients hospitalized for suspected COVID-19 infection.MethodsThis was a retrospective analysis of 324 consecutive patients admitted to Temple University Hospital. All hospitalized patients who had RT-PCR testing and HRCT were included in the study. HRCTs were classified as Category 1, 2 or 3. Patients were then divided into four groups based on HRCT category and RT-PCR swab results for analysis.ResultsThe average age of patients was 59.4 (±15.2) years and 123 (38.9%) were female. Predominant ethnicity was African American 148 (46.11%). 161 patients tested positive by RT-PCR, while 41 tested positive by HRCT. 167 (52.02%) had category 1 scan, 63 (19.63%) had category 2 scan and 91 (28.35%) had category 3 HRCT scans. There was substantial agreement between our radiologists for HRCT classification (κ = 0.64). Sensitivity and specificity of HRCT classification system was 77.6 and 73.7 respectively. Ferritin, LDH, AST and ALT were higher in Group 1 and D-dimers levels was higher in Group 3; differences however were not statistically significant.ConclusionDue to its high infectivity and asymptomatic transmission, until a highly sensitive and specific COVID-19 test is developed, HRCT should be incorporated into the assessment of patients who are hospitalized with suspected COVID-19.Key PointsKey QuestionCan High Resolution CT chest (HRCT) improve diagnostic accuracy of current Nasopharyngeal swab in suspected COVID-19 patients?Bottom LineIn this retrospective analysis, our novel HRCT classification identified 20% of all COVID-19 patients who had negative nasopharyngeal reverse transcriptase polymerase chain reaction (RT-PCR) tests but had HRCT findings consistent with COVID-19 pneumonia. These patients were ruled out for other infections and laboratory markers were similar to other RT-PCR positive patientsWhy Read onOur new HRCT classification when combined with RT-PCR can improve diagnostic accuracy while promptly improving triaging in COVID-19 patients.

scholarly journals Diagnostic accuracy estimates for COVID-19 RT-PCR and Lateral flow immunoassay tests with Bayesian latent class models

2020 ◽  
Author(s):  
Polychronis Kostoulas ◽  
Paolo Eusebi ◽  
Sonja Hartnack
Keyword(s):  
Diagnostic Accuracy ◽  
Symptom Onset ◽  
Latent Class ◽  
Reference Method ◽  
Latent Class Models ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Rt Pcr ◽  
The Cross ◽  
Class Models

Abstract The objective of this work was to estimate the diagnostic accuracy of RT-PCR and Lateral flow immunoassay tests (LFIA) for COVID-19, depending on the time post symptom onset. Based on the cross-classified results of RT-PCR and LFIA, we used Bayesian latent class models (BLCMs), which do not require a gold standard for the evaluation of diagnostics. Data were extracted from studies that evaluated LFIA (IgG and/or IgM) assays using RT-PCR as the reference method. The cross-classified results of LFIA and RT-PCR were analysed separately for the first, second and third week post symptom onset. The SeRT-PCR was 0.695 (95% probability intervals: 0.563; 0.837) for the first week and remained similar for the second and the third week. The SeIgG/M was 0.318 (0.229; 0.416) for the first week and increased steadily. It was 0.755 (0.673; 0.829) and 0.927 (0.881; 0.965) for the second and third week, respectively. Both tests had a high to absolute Sp, with point median estimates for SpRT-PCR being consistently higher. SpRT-PCR was 0.990 (0.980; 0.998) for the first week. The corresponding value for SpIgG/M was 0.962 (0.905; 0.998). Further, Sp estimates for each test did not differ between weeks. BLCMs provide a valid and efficient alternative for evaluating the rapidly evolving diagnostics for COVID-19, under various clinical settings and for different risk profiles.

scholarly journals Clinical performance of the point-of-care cobas Liat for detection of SARS-CoV-2 in 20 minutes: A multicenter study

2020 ◽  
Author(s):  
Glen Hansen ◽  
Jamie Marino ◽  
Zi-Xuan Wang ◽  
Kathleen G. Beavis ◽  
John Rodrigo ◽  
...  
Keyword(s):  
Influenza A ◽  
Clinical Performance ◽  
Point Of Care ◽  
Nasopharyngeal Swab ◽  
Molecular Testing ◽  
Rt Pcr ◽  
Percent Agreement ◽  
Individual Care ◽  
Pcr Technology ◽  
Acid Test

Background: Highly accurate testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the point of care (POC) is an unmet diagnostic need in emergency care and time-sensitive outpatient care settings. Reverse transcription-polymerase chain reaction (RT-PCR) technology is the gold-standard for SARS-CoV-2 diagnostics. Methods: We performed a multi-site United States (US) study comparing the clinical performance of the first US Food and Drug Administration (FDA) authorized POC RT-PCR test for detection of SARS-CoV-2 in 20 minutes, the cobas® Liat SARS-CoV-2 & Influenza A/B nucleic acid test, to the most widely used RT-PCR laboratory test, the cobas® 68/8800 SARS-CoV-2 test. Results: Clinical nasopharyngeal swab specimens from 444 patients with 357 evaluable specimens at five US clinical laboratories were enrolled from September 21, 2020 to October 23, 2020. The overall agreement between the Liat and 68/8800 systems for SARS-CoV-2 diagnostics was 98.6% (352/357). Using Liat, positive percent agreement for SARS-CoV-2 was 100% (162/162) and the negative percent agreement was 97.4% (190/195). Conclusion: The Liat is an RT-PCR POC test that provides highly accurate SARS-CoV-2 results in 20 minutes with equivalent performance to high-throughput laboratory molecular testing. Rapid RT-PCR testing at the POC can enable more timely infection control and individual care decisions for Coronavirus Disease 2019.

scholarly journals LUNG ULTRASOUND IN RULING OUT COVID-19 AMONG HEALTHCARE WORKERS IN TWO ITALIAN EMERGENCY DEPARTMENTS: A MULTICENTER STUDY.

2021 ◽  
Author(s):  
Roberto Copetti ◽  
Giulia Amore ◽  
Caterina Giudice ◽  
Daniele Orso ◽  
Silvia Cola ◽  
...  
Keyword(s):  
Negative Predictive Value ◽  
Predictive Value ◽  
Emergency Departments ◽  
Healthcare Workers ◽  
Lung Ultrasound ◽  
False Negative ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Negative Case ◽  
Adjudication Committee

Purpose: The high percentage of asymptomatic patients and the non-high sensitivity of real-time reverse transcription-polymerase chain reaction (RT-PCR) test on nasopharyngeal swab cause some healthcare workers to be infected but asymptomatic and a source of spread of the epidemic. This study aimed to verify if the lung ultrasound (LUS) had enough high negative predictive value to rule out coronavirus disease 2019 (COVID-19) among a population of healthcare workers operating in the Emergency Department. Methods: A multicenter prospective observational study was conducted, enrolling healthcare workers among the staff of two Emergency Departments in Northeast Italy. The definitive diagnosis of COVID-19 was established by an adjudication committee, based on the clinical data and RT-PCR on nasopharyngeal swab result. Results: From March 30, 2020, to April 22, 2020, we enrolled 155 cases. The adjudication committee determined two true positives for COVID-19. Twenty-one healthcare workers presented suggestive symptoms (2 true positives and 19 false positives). The nasopharyngeal swab was positive in one case (1 false-negative case). LUS was suggestive for COVID-19 pneumonia in 4 cases (2 false-positive cases). The diagnostic accuracy of LUS was 98.7% (95% CI 95.4%-99.8%). The sensitivity and the specificity of LUS were 100% (95% CI 15.8% -100%) and 98.7% (95% CI 95.4% - 99.8%), respectively. The negative predictive value was 100% (95% CI 100% -100%). Conclusion: LUS has a good enough negative predictive value for ruling out COVID-19 in a population of healthcare workers exposed to COVID-19.

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