scholarly journals Direct Comparison of SARS Co-V-2 Nasal RT- PCR and Rapid Antigen Test (BinaxNOWTM) at a Community Testing Site During an Omicron Surge

2022 ◽  
Author(s):  
John Schrom ◽  
Carina Marquez ◽  
Genay Pilarowski ◽  
Grace Wang ◽  
Anthea Mitchell ◽  
...  
Keyword(s):  
San Francisco ◽  
High Viral Load ◽  
Antigen Test ◽  
Rt Pcr ◽  
Repeat Testing ◽  
Single Antigen ◽  
Testing Site ◽  
Antigen Testing ◽  
Test Result ◽  
Community Site

In 731 persons seeking COVID-19 testing at a walk-up San Francisco community site in January 2022, simultaneous nasal rapid antigen testing (BinaxNOWTM) and RT-PCR testing was performed. There were 296 (40.5%) positive tests by RT-PCR; 97% of a random sample were the omicron variant. Sensitivity of a single antigen test was 95.2% (95% CI 92-98%); 82.1% (95% CI 77-87%) and 65.2% (95% CI 60-70%) for Ct threshold of < 30, < 35 and no threshold, respectively. A single BinaxNowTM rapid antigen test detected 95% of high viral load omicron cases from nasal specimens. As currently recommended, repeat testing should be done for high- risk persons with an initial negative antigen test result.

scholarly journals Performance characteristics of a rapid SARS-CoV-2 antigen detection assay at a public plaza testing site in San Francisco

2020 ◽  
Author(s):  
Genay Pilarowski ◽  
Paul Lebel ◽  
Sara Sunshine ◽  
Jamin Liu ◽  
Emily Crawford ◽  
...  
Keyword(s):  
Viral Load ◽  
San Francisco ◽  
High Viral Load ◽  
Performance Characteristics ◽  
Viral Rna ◽  
Antigen Test ◽  
Rt Pcr ◽  
Detection Assay ◽  
Community Transmission ◽  
Testing Site

ABSTRACTWe evaluated the performance of the Abbott BinaxNOW™ Covid-19 rapid antigen test to detect virus among persons, regardless of symptoms, at a public plaza site of ongoing community transmission. Titration with cultured clinical SARS-CoV-2 yielded a human observable threshold between 1.6×104-4.3×104 viral RNA copies (cycle threshold (Ct) of 30.3-28.8 in this assay). Among 878 subjects tested, 3% (26/878) were positive by RT-PCR, of which 15/26 had a Ct<30, indicating high viral load. 40% (6/15) of Ct<30 were asymptomatic. Using this Ct<30 threshold for Binax-CoV2 evaluation, the sensitivity of the Binax-CoV2 was 93.3% (14/15), 95% CI: 68.1-99.8%, and the specificity was 99.9% (855/856), 95% CI: 99.4-99.9%.

scholarly journals Performance characteristics of a rapid SARS-CoV-2 antigen detection assay at a public plaza testing site in San Francisco

2021 ◽  
Author(s):  
Genay Pilarowski ◽  
Paul Lebel ◽  
Sara Sunshine ◽  
Jamin Liu ◽  
Emily Crawford ◽  
...  
Keyword(s):  
Viral Load ◽  
San Francisco ◽  
High Viral Load ◽  
Performance Characteristics ◽  
Viral Rna ◽  
Antigen Test ◽  
Rt Pcr ◽  
Detection Assay ◽  
Community Transmission ◽  
Testing Site

Abstract We evaluated the performance of the Abbott BinaxNOW TM Covid-19 rapid antigen test (Binax-CoV2) to detect virus among persons, regardless of symptoms, at a public plaza site of ongoing community transmission. Titration with cultured SARS-CoV-2 yielded a human observable threshold between 1.6x10 4-4.3x10 4 viral RNA copies (cycle threshold (Ct) of 30.3-28.8). Among 878 subjects tested, 3% (26/878) were positive by RT-PCR, of which 15/26 had Ct&lt;30, indicating high viral load. 40% (6/15) of Ct&lt;30 were asymptomatic. Using this Ct&lt;30 threshold for Binax-CoV2 evaluation, the sensitivity of Binax-CoV2 was 93.3% (14/15), 95% CI: 68.1-99.8%, and the specificity was 99.9% (855/856), 95% CI: 99.4-99.9%.

scholarly journals Comparison of SARS-CoV-2 antigen electrochemiluminescence immunoassay to RT-PCR assay for laboratory diagnosis of COVID-19 in Peshawar

Diagnosis ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bilal Iqbal ◽  
Maria Khan ◽  
Noman Shah ◽  
Mirza Muhammad Dawood ◽  
Valeed Jehanzeb ◽  
...  
Keyword(s):  
Laboratory Diagnosis ◽  
Cross Sectional Study ◽  
Antigen Test ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Cross Sectional ◽  
Viral Loads ◽  
Testing Algorithms ◽  
Frequent Testing ◽  
Antigen Testing

Abstract Objectives Antigen based rapid diagnostic tests possesses a potential to be utilized along with Gold standard methods to detect Covid-19 infection to cope with the demand of testing. The aim of this study was to determine diagnostic accuracy of electrochemiluminescence based automated antigen detection immunoassay comparing with molecular based test RT-PCR (Covid-19). Methods It was a cross-sectional study conducted in RMI Peshawar, from 1st April 2021 till 30th April 2021. The study comprised 170 individuals who were suspected of having Covid-19. Nasopharyngeal samples taken from suspected individuals were analyzed by RT-PCR and automated antigen test (Elecsys SARS-CoV-2 Antigen) simultaneously. The correlation of SARS-CoV-2 antigen with PCR positive and negative cases was analyzed for specificity, sensitivity respectively. Results The ECLIA based Elecsys antigen test (Roche) revealed overall sensitivity 72%, specificity 95% and accuracy of 94.9%. Sensitivity of antigen test progressively declined from 94.3% in Ct <25 to 70.8% in Ct 26–29 and then to 47.2% in Ct 30–35. Conclusions Based on the findings of our study we conclude that automated antigen testing (Elecsys SARS-CoV-2 Antigen) cannot replace molecular based testing like RT PCR. Elecsys SARS-CoV-2 Ag test should be used complementary to RT-PCR in testing algorithms. Frequent testing strategy should be adopted while using automated antigen testing to overcome its limitation in individuals with low viral loads.

scholarly journals High Sensitivity and NPV for BinaxNOW Rapid Antigen Test in Children at a Mass Testing Site During Prevalent Delta Variant

2022 ◽  
Author(s):  
Kristie J Sun ◽  
Mary Jane E Vaeth ◽  
Matthew L Robinson ◽  
Maryam Elhabashy ◽  
Ishaan Gupta ◽  
...  
Keyword(s):  
Predictive Value ◽  
High Sensitivity ◽  
High Volume ◽  
Educational Opportunities ◽  
Antigen Test ◽  
Sample Collection ◽  
Rt Pcr ◽  
Polymerase Chain ◽  
Testing Site ◽  
Antigen Tests

SARS-CoV-2 continues to develop new, increasingly infectious variants, such as delta and omicron. Here, we evaluate the efficacy of the Abbott BinaxNOW Rapid Antigen Test against the gold standard of Reverse Transcription Polymerase Chain Reaction (RT-PCR) in 1054 pediatric participants presenting to a state-owned high-volume Coronavirus Disease 2019 (COVID-19) testing site. During the testing period, the delta variant was predominant. Prior to sample collection, symptomatic and exposure status was collected for all participants based on Centers for Disease Control (CDC) criteria. RT-PCR results demonstrated an overall prevalence rate of 5.2%. For all participants, the sensitivity of the rapid antigen tests was 92.7% (95% CI 82.4% - 98.0%) and specificity was 98.0% (95% CI 97.0%-98.8%). For symptomatic participants, the sensitivity was 92.3% (95% CI 74.9% - 99.1%), specificity was 96.6% (95% CI 93.6%- 98.4%), positive predictive value (PPV) was 72.7% (95% CI 54.5% - 86.7%) and negative predictive value (NPV) was 99.2% (95% CI 98.2% - 100%). Among asymptomatic participants, the sensitivity was 92.6% (95% CI 75.7% - 99.1%), specificity was 98.6% (95% CI 97.5% - 99.3%) the PPV was 71.4% (95% CI 53.7% - 85.4%) and the NPV was 99.7% (95% CI 99.0% - 100%). Our reported sensitivity and NPV are higher than other pediatric studies, but specificity and PPV are lower. Importance Children are especially impacted by the disease and its ability to disrupt educational opportunities. Although vaccinations have been approved for children 5 years and older, many children remain unvaccinated. Widespread testing may improve the ability for children to remain in in-person activities, minimizing absences from school and extracurriculars. Highly accurate rapid antigen tests may be vital to containing future COVID-19 waves while mitigating detrimental effects.

scholarly journals Characteristics of children and antigen test performance at a SARS-CoV-2 community testing site

2021 ◽  
Author(s):  
Laura Ford ◽  
Melissa J. Whaley ◽  
Melisa M. Shah ◽  
Phillip P. Salvatore ◽  
Hannah E. Segaloff ◽  
...  
Keyword(s):  
Test Performance ◽  
Point Of Care ◽  
Lower Sensitivity ◽  
Antigen Test ◽  
Rt Pcr ◽  
Culture Methods ◽  
Viral Culture ◽  
Asymptomatic Children ◽  
Testing Site ◽  
Antigen Tests

Background: Performance characteristics of SARS-CoV-2 antigen tests among children are limited despite the need for point-of-care testing in school and childcare settings. We describe children seeking SARS-CoV-2 testing at a community site and compare antigen test performance to real-time reverse transcription-polymerase chain reaction (RT-PCR) and viral culture. Methods: Two anterior nasal specimens were self-collected for BinaxNOW antigen and RT-PCR testing, along with demographics, symptoms, and exposure information from individuals ≥5 years at a community testing site. Viral culture was attempted on residual antigen or RT-PCR positive specimens. Demographic and clinical characteristics, and the performance of SARS-CoV-2 antigen tests, were compared among children (<18 years) and adults. Results: About one in ten included specimens were from children (225/2110); 16.4% (37/225) were RT-PCR positive. Cycle threshold values were similar among RT-PCR positive specimens from children and adults (22.5 vs 21.3, p=0.46) and among specimens from symptomatic and asymptomatic children (22.5 vs 23.2, p=0.39). Sensitivity of antigen test compared to RT-PCR was 73.0% (27/37) among specimens from children and 80.8% (240/297) among specimens from adults; among specimens from children, specificity was 100% (188/188), positive and negative predictive value were 100% (27/27) and 94.9% (188/198) respectively. Virus was isolated from 51.4% (19/37) of RT-PCR positive pediatric specimens; all 19 had positive antigen test results. Conclusions : With lower sensitivity relative to RT-PCR, antigen tests may not diagnose all positive COVID-19 cases; however, antigen testing identified children with live SARS-CoV-2 virus.

scholarly journals Clinical evaluation of the Roche/SD Biosensor rapid antigen test with symptomatic, non-hospitalized patients in a municipal health service drive-through testing site

2020 ◽  
Author(s):  
Zsὁfia Iglὁi ◽  
Jans Velzing ◽  
Janko van Beek ◽  
David van de Vijver ◽  
Georgina Aron ◽  
...  
Keyword(s):  
Viral Load ◽  
Rapid Test ◽  
Contact Tracing ◽  
Gene Copy ◽  
Nasopharyngeal Swab ◽  
List Type ◽  
Antigen Test ◽  
Rt Pcr ◽  
Outbreak Management ◽  
Testing Site

AbstractBackgroundRapid detection of infectious individuals is essential in stopping the further spread of SARS-CoV-2. Although rapid antigen test is not as sensitive as the gold standard RT-PCR, the time to result is decreased by day(s), strengthening the effectiveness of contact tracing.MethodsThe Roche/SD Biosensor lateral flow antigen rapid test was evaluated in a mild symptomatic population at a large drive through testing site. A second nasopharyngeal swab was directly tested with the rapid test on site and results were compared to RT-PCR and virus culture. Date of onset and symptoms were analysed using data from a clinical questionnaire.ResultsWe included 970 persons with complete data. Overall sensitivity and specificity were 84.9% (CI95% 79.1-89.4) and 99.5% (CI95% 98.7-99.8) which translated into a positive predictive value of 97.5% (CI95% 94.0-99.5) under the current regional PCR positivity of 19.2%. Sensitivity for people with high loads of viral RNA (ct <30, 2.17E+05 E gene copy/ml) and who presented within 7 days since symptom onset increased to 95.8% (CI95% 90.5-98.2). Band intensity and time to result correlated strongly with viral load thus strong positive bands could be read before the recommended time. Around 98% of all viable specimen with ct <30 were detected successfully indicating that the large majority of infectious people can be captured with this test.ConclusionAntigen rapid tests can detect mildly symptomatic cases in the early phase of disease thereby identifying the most infectious individuals. Using this assay can have a significant value in the speed and effectiveness of SARS-CoV-2 outbreak management.SummaryPeople with early onset and high viral load were detected with 98.2% sensitivity.97% of individuals in which virus could be cultured were detected by the rapid test.This test is suitable to detect mild symptomatic cases.

scholarly journals Diagnostic performance and characteristics of anterior nasal collection for the SARS-CoV-2 antigen test: a prospective study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuto Takeuchi ◽  
Yusaku Akashi ◽  
Daisuke Kato ◽  
Miwa Kuwahara ◽  
Shino Muramatsu ◽  
...  
Keyword(s):  
Prospective Study ◽  
Clinical Utility ◽  
Diagnostic Performance ◽  
Antigen Test ◽  
Sample Collection ◽  
Rt Pcr ◽  
Reverse Transcription Pcr ◽  
Moderate Sensitivity ◽  
Testing Site ◽  
A Prospective Study

AbstractThe clinical utility of antigen test using anterior nasal samples has not been well evaluated. We conducted a prospective study in a drive-through testing site located at a PCR center to evaluate the diagnostic performance of the antigen test QuickNavi-COVID19 Ag using anterior nasal samples and to compare the degrees of coughs or sneezes induction and the severity of pain between anterior nasal collection and nasopharyngeal collection. The study included a total of 862 participants, of which 91.6% were symptomatic. The median duration from symptom onset to sample collection was 2.0 days. Fifty-one participants tested positive for severe acute respiratory syndrome coronavirus 2 on reverse transcription PCR (RT-PCR) with nasopharyngeal samples, and all of them were symptomatic. In comparison to the findings of RT-PCR, the antigen test using anterior nasal samples showed 72.5% sensitivity (95% confidence interval [CI] 58.3–84.1%) and 100% specificity (95% CI 99.3–100%). Anterior nasal collection was associated with a significantly lower degree of coughs or sneezes induction and the severity of pain in comparison to nasopharyngeal collection (p < 0.001). The antigen test using anterior nasal samples showed moderate sensitivity in symptomatic patients who were at the early stages of the disease course but was less painful and induced fewer coughs or sneezes.

scholarly journals Head-to-head comparison of SARS-CoV-2 antigen-detecting rapid test with professional-collected anterior nasal versus nasopharyngeal swab

2020 ◽  
Author(s):  
Andreas K. Lindner ◽  
Olga Nikolai ◽  
Chiara Rohardt ◽  
Susen Burock ◽  
Claudia Hülso ◽  
...  
Keyword(s):  
Healthcare Professionals ◽  
Rapid Test ◽  
High Viral Load ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Test Procedures ◽  
Testing Strategies ◽  
Percent Agreement ◽  
Accuracy Study ◽  
Antigen Testing

AbstractBackgroundNasopharyngeal (NP) swab samples for antigen-detecting rapid diagnostic tests (Ag-RDTs) require qualified healthcare professionals and are frequently perceived as uncomfortable by patients.MethodsWe performed a manufacturer-independent, prospective diagnostic accuracy study, comparing professional-collected anterior nasal (AN) to nasopharyngeal swab, using the test kits of a WHO-listed SARS-CoV-2 Ag-RDT (STANDARD Q COVID-19 Ag Test, SD Biosensor), which is also being distributed by Roche. Individuals with high suspicion for COVID-19 infection were tested. The reference standard was RT-PCR using a combined oro-/nasopharyngeal swab sample. Percent positive and negative agreement, as well as sensitivity and specificity were calculated.ResultsAmong the 179 participants, 41 (22.9%) tested positive for SARS-CoV-2 by RT-PCR. The positive percent agreement of the two different sampling techniques for the Ag-RDT was 93.5% (CI 79.3-98.2). The negative percent agreement was 95.9% (CI 91.4-98.1). The Ag-RDT with AN-sampling showed a sensitivity of 80.5% (33/41 PCR positives detected; CI 66.0-89.8) and specificity of 98.6% (CI 94.9-99.6) compared to RT-PCR. The sensitivity with NP-sampling was 73.2% (30/41 PCR positives detected; CI 58.1-84.3) and specificity was 99.3% (CI 96.0-100). In patients with high viral load (>7.0 log10 RNA SARS-CoV2/swab), the sensitivity of the Ag-RDT with AN-sampling was 100% and 94.7% with NP-sampling.ConclusionThis study demonstrates that sensitivity of a WHO-listed SARS-CoV-2 Ag-RDT using a professional AN-sampling kit is at least equal to that of the NP-sampling kit, although confidence intervals overlap. Of note, differences in the IFUs of the test procedures could have contributed to different sensitivities. AN-sampling can be performed with less training, reduces patient discomfort, and it enables scaling of antigen testing strategies. Additional studies of patient self-sampling should be considered to further facilitate the scaling-up of Ag-RDT testing.

scholarly journals Five Antigen Tests for SARS-CoV-2: Virus Viability Matters

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 684
Author(s):  
Miroslav Homza ◽  
Hana Zelena ◽  
Jaroslav Janosek ◽  
Hana Tomaskova ◽  
Eduard Jezo ◽  
...  
Keyword(s):  
False Negative ◽  
Antigen Test ◽  
Rt Pcr ◽  
False Negatives ◽  
Predictive Values ◽  
Asymptomatic Patients ◽  
High Prevalence ◽  
Antigen Tests ◽  
Antigen Testing ◽  
Excellent Tool

Antigen testing for SARS-CoV-2 (AGT) is generally considered inferior to RT-PCR testing in terms of sensitivity. However, little is known about the infectiousness of RT-PCR positive patients who pass undetected by AGT. In a screening setting for mildly symptomatic or asymptomatic patients with high COVID-19 prevalence (30–40%), 1141 patients were tested using one of five AGTs and RT-PCR. Where the results differed, virus viability in the samples was tested on cell culture (CV-1 cells). The test battery included AGTs by JOYSBIO, Assure Tech, SD Biosensor, VivaChek Biotech and NDFOS. Sensitivities of the ATGs compared to RT-PCR ranged from 42% to 76%. The best test yielded a 76% sensitivity, 97% specificity, 92% positive, and 89% negative predictive values, respectively. However, in the best performing ATG tests, almost 90% of samples with “false negative” AGT results contained no viable virus. Corrected on the virus viability, sensitivities grew to 81%–97% and, with one exception, the tests yielded high specificities >96%. Performance characteristics of the best test after adjustment were 96% sensitivity, 97% specificity, 92% positive, and 99% negative predictive values (high prevalence population). We, therefore, believe that virus viability should be considered when assessing the AGT performance. Also, our results indicate that a well-performing antigen test could in a high-prevalence setting serve as an excellent tool for identifying patients shedding viable virus. We also propose that the high proportion of RT-PCR-positive samples containing no viable virus in the group of “false negatives” of the antigen test should be further investigated with the aim of possibly preventing needless isolation of such patients.

scholarly journals Association between viral load and positivization time of a SARS-CoV-2 rapid antigen test in routine nasopharyngeal specimens

2021 ◽  
Author(s):  
Gian Luca Salvagno ◽  
Brandon Michael Henry ◽  
Simone De Nitto ◽  
Laura Pighi ◽  
Giuseppe Lippi
Keyword(s):  
Viral Load ◽  
Diagnostic Testing ◽  
Area Under The Curve ◽  
High Viral Load ◽  
Antigen Test ◽  
Potential Association ◽  
Antigen Tests ◽  
Antigen Testing ◽  
Spearman’S Correlation ◽  
Positive Results

Abstract Background: Rapid SARS-CoV-2 antigen tests are potentially useful tools for screening carriers with high viral load. This study was aimed to assess the potential association between viral load and positivization time of a manual SARS-CoV-2 commercial antigen test in routine nasopharyngeal specimens. Methods: In a sample of subjects undergoing routine diagnostic testing, SARS-CoV-2 positivity of nasopharyngeal samples was assayed with both molecular (Altona Diagnostics RealStar SARS-CoV-2 RT-PCR Kit) and antigenic (Roche SARS-CoV-2 Rapid Antigen Test) tests. Positivization time of rapid antigen test was correlated and compared with viral load expressed as mean of SARS-CoV-2 E/S genes cycle threshold (Ct) values.Results: The study sample consisted of 106 patients (median age 48 years, 55 women) with positive results of rapid SARS-CoV-2 antigen testing. A highly significant Spearman’s correlation was found between mean SARS-CoV-2 E/S genes Ct values and positivization time of manual antigen test (r= 0.70; p<0.001). The positivization time of rapid SARS-CoV-2 antigen test displayed an area under the curve of 0.82 (95%CI, 0.74-0.89) for predicting nasopharyngeal samples with high viral load (i.e., mean Ct <20). A positivization time cut-off of 32 sec had 94.9% sensitivity and 58.2% specificity for detecting specimens with high viral load. The overall agreement between mean Ct value <20 and positivization time <32 sec was 70.8%.Conclusions: Positivization time of rapid SARS-CoV-2 antigen tests may provide easy and rapid information on viral load, thus making this type of manual assay potentially suitable for quick and reliable detection and isolation of super-carries.

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