scholarly journals Evaluation of a SARS-CoV-2 rapid antigen test: potential to help reduce community spread?

2020 ◽  
Author(s):  
Tuna Toptan ◽  
Lisa Eckermann ◽  
Annika E. Pfeiffer ◽  
Sebastian Hoehl ◽  
Sandra Ciesek ◽  
...  
Keyword(s):  
Cell Culture ◽  
Clinical Performance ◽  
Cross Reactivity ◽  
Clinical Samples ◽  
Antigen Test ◽  
Rigorous Analysis ◽  
Viral Loads ◽  
Test Sensitivity ◽  
Antigen Tests ◽  
Asymptomatic Individuals

ABSTRACTSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can spread from symptomatic patients with COVID-19, but also from asymptomatic individuals. Therefore, robust surveillance and timely interventions are essential for the control of virus spread within the community. In this regard the frequency of testing and speed of reporting, but not the test sensitivity alone, play a crucial role. In order to reduce the costs and meet the expanding demands in real-time RT-PCR (rRT-PCR) testing for SARS-CoV-2, complementary assays, such as rapid antigen tests, have been developed. Rigorous analysis under varying conditions is required to assess the clinical performance of these tests and to ensure reproducible results. We evaluated the sensitivity and specificity of a recently licensed rapid antigen test using 137 clinical samples in two institutions. Test sensitivity was between 88.2-89.6% when applied to samples with viral loads typically seen in infectious patients. Of 32 rRT-PCR positive samples, 19 demonstrated infectivity in cell culture, and 84% of these samples were reactive with the antigen test. Seven full-genome sequenced SARS-CoV-2 isolates and SARS-CoV-1 were detected with this antigen test, with no cross-reactivity against other common respiratory viruses. Numerous antigen tests are available for SARS-CoV-2 testing and their performance to detect infectious individuals may vary. Head-to-head comparison along with cell culture testing for infectivity may prove useful to identify better performing antigen tests. The antigen test analyzed in this study is easy-to-use, inexpensive, and scalable. It can be helpful in monitoring infection trends and thus has potential to reduce transmission.

scholarly journals The Comparative Clinical Performance of Four SARS-CoV-2 Rapid Antigen Tests and Their Correlation to Infectivity In Vitro

2021 ◽  
Vol 10 (2) ◽  
pp. 328 ◽  
Author(s):  
Niko Kohmer ◽  
Tuna Toptan ◽  
Christiane Pallas ◽  
Onur Karaca ◽  
Annika Pfeiffer ◽  
...  
Keyword(s):  
Cell Culture ◽  
Large Scale ◽  
Clinical Performance ◽  
Immunofluorescence Assay ◽  
Clinical Samples ◽  
Chain Reaction ◽  
Lateral Flow Assays ◽  
Polymerase Chain ◽  
Antigen Tests

Due to globally rising numbers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, resources for real-time reverse-transcription polymerase chain reaction (rRT-PCR)-based testing have been exhausted. In order to meet the demands of testing and reduce transmission, SARS-CoV-2 antigen-detecting rapid diagnostic tests (Ag-RDTs) are being considered. These tests are fast, inexpensive, and simple to use, but whether they detect potentially infectious cases has not been well studied. We evaluated three lateral flow assays (RIDA®QUICK SARS-CoV-2 Antigen (R-Biopharm), SARS-CoV-2 Rapid Antigen Test (Roche)), and NADAL® COVID-19 Ag Test (Nal von Minden GmbH, Regensburg, Germany) and one microfluidic immunofluorescence assay (SARS-CoV-2 Ag Test (LumiraDx GmbH, Cologne, Germany)) using 100 clinical samples. Diagnostic rRT-PCR and cell culture testing as a marker for infectivity were performed in parallel. The overall Ag-RDT sensitivity for rRT-PCR-positive samples ranged from 24.3% to 50%. However, for samples with a viral load of more than 6 log10 RNA copies/mL (22/100), typically seen in infectious individuals, Ag-RDT positivity was between 81.8% and 100%. Only 51.6% (33/64) of the rRT-PCR-positive samples were infectious in cell culture. In contrast, three Ag-RDTs demonstrated a more significant correlation with cell culture infectivity (61.8–82.4%). Our findings suggest that large-scale SARS-CoV-2 Ag-RDT-based testing can be considered for detecting potentially infective individuals and reducing the virus spread.

Clinical assessment of the Roche SARS-CoV-2 rapid antigen test

Diagnosis ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gian Luca Salvagno ◽  
Gianluca Gianfilippi ◽  
Damiano Bragantini ◽  
Brandon M. Henry ◽  
Giuseppe Lippi
Keyword(s):  
Clinical Assessment ◽  
Clinical Performance ◽  
Point Of Care ◽  
High Viral Load ◽  
Rapid Screening ◽  
Clinical Samples ◽  
Molecular Testing ◽  
Antigen Test ◽  
Community Screening ◽  
Final Study

Abstract Objectives Novel point-of-care antigen assays present a promising opportunity for rapid screening of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. The purpose of this study was the clinical assessment of the new Roche SARS-CoV-2 Rapid Antigen Test. Methods The clinical performance of Roche SARS-CoV-2 Rapid Antigen Test was evaluated vs. a reverse transcription polymerase chain reaction (RT-PCR) laboratory-based assay (Seegene AllplexTM2019-nCoV) in nasopharyngeal swabs collected from a series of consecutive patients referred for SARS-CoV-2 diagnostics to the Pederzoli Hospital (Peschiera del Garda, Verona, Italy) over a 2-week period. Results The final study population consisted of 321 consecutive patients (mean age, 46 years and IQR, 32–56 years; 181 women, 56.4%), with 149/321 (46.4%) positive for SARS-CoV-2 RNA via the Seegene AllplexTM2019-nCoV Assay, and 109/321 (34.0%) positive with Roche SARS-CoV-2 Rapid Antigen Test, respectively. The overall accuracy of Roche SARS-CoV-2 Rapid Antigen Test compared to molecular testing was 86.9%, with 72.5% sensitivity and 99.4% specificity. Progressive decline in performance was observed as cycle threshold (Ct) values of different SARS-CoV-2 gene targets increased. The sensitivity was found to range between 97–100% in clinical samples with Ct values <25, between 50–81% in those with Ct values between 25 and <30, but low as 12–18% in samples with Ct values between 30 and <37. Conclusions The clinical performance of Roche SARS-CoV-2 Rapid Antigen Test is excellent in nasopharyngeal swabs with Ct values <25, which makes it a reliable screening test in patients with high viral load. However, mass community screening would require the use of more sensitive techniques.

scholarly journals Clinical and experimental factors that affect the reported performance characteristics of rapid testing for SARS-CoV-2

2021 ◽  
Author(s):  
Valentin Parvu ◽  
Devin Gary ◽  
Joseph Mann ◽  
Yu-Chih Lin ◽  
Dorsey Mills ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Disease Diagnosis ◽  
Upper Respiratory Tract ◽  
Antigen Test ◽  
Test Sensitivity ◽  
Viral Culture ◽  
Upper Respiratory ◽  
Asymptomatic Individuals ◽  
Design Factors

ABSTRACT Tests that detect the presence of SARS-CoV-2 antigen in clinical specimens from the upper respiratory tract can provide a rapid means of COVID-19 disease diagnosis and help identify individuals that may be infectious and should isolate to prevent SARS-CoV-2 transmission. This systematic review assesses the diagnostic accuracy of SARS-CoV-2 antigen detection in COVID-19 symptomatic and asymptomatic individuals compared to RT-qPCR, and summarizes antigen test sensitivity using meta-regression. In total, 83 studies were included that compared SARS-CoV-2 rapid antigen lateral flow testing (RALFT) to RT-qPCR for SARS-CoV-2. Generally, the quality of the evaluated studies was inconsistent, nevertheless, the overall sensitivity for RALFT was determined to be 75.0% (95% confidence interval [CI]: 71.0-78.0). Additionally, RALFT sensitivity was found to be higher for symptomatic versus asymptomatic individuals and was higher for a symptomatic population within 7 days from symptom onset (DSO) compared to a population with extended days of symptoms. Viral load was found to be the most important factor for determining SARS-CoV-2 antigen test sensitivity. Other design factors, such as specimen storage and anatomical collection type, also affect the performance of RAFLT. RALFT and RT-qPCR testing both achieve high sensitivity when compared to SARS-CoV-2 viral culture.

scholarly journals An assessment of a rapid SARS-CoV-2 antigen test in Bangladesh

2021 ◽  
Author(s):  
Zannat Kawser ◽  
Mohabbat Hossain ◽  
Sara Suliman ◽  
Shahin Lockman ◽  
Jesse Gitaka ◽  
...  
Keyword(s):  
False Positive ◽  
Rapid Test ◽  
Field Evaluation ◽  
Ease Of Use ◽  
Large Field ◽  
Antigen Test ◽  
Rt Pcr ◽  
Rapid Antigen Detection Test ◽  
Antigen Tests ◽  
Asymptomatic Individuals

Early detection of SARS-CoV-2 infection is crucial to prevent the spread of the virus. In this study, we evaluated the performance of a commercial rapid antigen detection test, BD Veritor, and compared this (and another rapid test, Standard Q) against a gold-standard of nasopharyngeal (NP) swab tested by reverse transcription-polymerase chain reaction (RT-PCR) in prospectively recruited adults in Dhaka, Bangladesh. We compared the sensitivity and specificity of the two rapid antigen tests against RT-PCR results in 130 symptomatic and 130 asymptomatic adults. In addition, we evaluated the suitability and ease-of-use of the BD Veritor test in a subsample of study participants (n=42) and implementers (n=5). The sensitivity of the BD Veritor rapid antigen 66 test was 70% in symptomatic (95% confidence interval [CI]: 51-85%) and 87% (95% CI: 69-96%) in asymptomatic individuals with positive SARSCoV-2 RT-PCR, for overall sensitivity of 78% (95% CI: 66-88%). The sensitivity of the Standard Q rapid antigen test was 63% (95% CI: 44-69 80%) in symptomatic and 73% (95% CI: 54-87%) in asymptomatic individuals. One false positive in BD Veritor test (specificity 99.5) and no false positive in Standard Q tests were observed (specificity 100%). The BD Veritor rapid antigen test was 78% sensitive when compared with RT-PCR irrespective of the cycle threshold (Ct) levels in this evaluation in Bangladesh. The implementation evaluation data showed good acceptability in the field settings. This warrants large field evaluation as well as use of the rapid antigen test for quick assessment of SARS-CoV-2 for containment of epidemics in the country.

scholarly journals Prospective analytical performance evaluation of the QuickNavi™-COVID19 Ag for asymptomatic individuals

2021 ◽  
Author(s):  
Yoshihiko Kiyasu ◽  
Yuto Takeuchi ◽  
Yusaku Akashi ◽  
Daisuke Kato ◽  
Miwa Kuwahara ◽  
...  
Keyword(s):  
Real Time ◽  
Diagnostic Performance ◽  
False Positives ◽  
Clinical Samples ◽  
Lower Sensitivity ◽  
Antigen Test ◽  
Rt Pcr ◽  
Asymptomatic Group ◽  
Asymptomatic Volunteers ◽  
Asymptomatic Individuals

AbstractIntroductionAntigen testing may help screen for and detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in asymptomatic individuals. However, limited data regarding the diagnostic performance of antigen tests for this group are available.MethodsWe used clinical samples to prospectively evaluate the analytical and clinical performance of the antigen test QuickNavi™-COVID19 Ag. This study was conducted at a PCR center between October 7, 2020 and January 9, 2021. Two nasopharyngeal samples per patient were obtained with flocked swabs; one was used for the antigen test, and the other for real-time reverse transcription PCR (RT-PCR). The diagnostic performance of the antigen test was compared between asymptomatic and symptomatic patients, and the RT-PCR results were used as a reference.ResultsAmong the 1,934 collected samples, SARS-CoV-2 was detected by real-time RT-PCR in 188 (9.7%); 76 (40.4%) of these samples were from asymptomatic individuals. Over half of the total samples (1,073; 55.5%) were obtained from asymptomatic volunteers. The sensitivity of the antigen test was significantly lower for asymptomatic group than for symptomatic patients (67.1% vs 89.3%, p < 0.001). The specificity was 100% for both groups, and no false positives were observed among all 1,934 samples. The median Ct value for the asymptomatic group was significantly higher than that of the symptomatic group (24 vs 20, p < 0.001).ConclusionsThe QuickNavi™-COVID19 Ag showed a lower sensitivity for asymptomatic group than for symptomatic patients. However, its specificity was consistently high, and no false positives were found in this study.

scholarly journals Diagnostic Performance of a Rapid Antigen Test Compared with the Reverse Transcription Polymerase Chain Reaction for SARS-CoV-2 Detection in Asymptomatic Individuals Referring to a Drive-in Testing Facility

COVID ◽  
2021 ◽  
Vol 1 (4) ◽  
pp. 784-789
Author(s):  
Fabio Lombardo ◽  
Gianluca Triolo ◽  
Biao Yang ◽  
Zhonghua Liu ◽  
Paolo Maiuri ◽  
...  
Keyword(s):  
Prospective Observational Study ◽  
High Specificity ◽  
Nucleic Acid Detection ◽  
Antigen Test ◽  
Chain Reaction ◽  
Viral Loads ◽  
Assay Performance ◽  
Testing Facility ◽  
Polymerase Chain ◽  
Asymptomatic Individuals

Quick and reliable identification of severe acute respiratory syndrome coronavirus SARS-CoV-2 in the population is required to manage the COVID-19 pandemic. This is a prospective observational study of diagnostic accuracy. Paired swab samples from 317 asymptomatic individuals referring to a drive-in testing facility were tested in parallel by means of the rapid antigen test developed by Jiangsu Bioperfectus Technologies and routine nucleic acid detection. Overall specificity was 100% and sensitivity was 49% but reached 87% at higher viral loads (Ct < 25). In this study, the antigen detection test showed high specificity and good sensitivity in asymptomatic individuals carrying higher viral loads. The assay performance worsened with lower viral loads, making it useful when a rapidly deployable test is essential and to assess a potential risk of immediate transmission in the community, but not recommended for testing asymptomatic individuals.

scholarly journals Validation of the STANDARD Q COVID-19 antigen test in Vojvodina, Serbia

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247606
Author(s):  
Mioljub Ristić ◽  
Nataša Nikolić ◽  
Velibor Čabarkapa ◽  
Vesna Turkulov ◽  
Vladimir Petrović
Keyword(s):  
Diagnostic Performance ◽  
Clinical Performance ◽  
Low Cost ◽  
Care Facility ◽  
Health Care Facility ◽  
High Sensitivity ◽  
Antigen Test ◽  
Viral Loads ◽  
Novi Sad ◽  
Strong Agreement

Background Since COVID-19 pandemic is a global crisis, tests with high sensitivity and specificity are crucial for the identification and management of COVID-19 patients. There is an urgent need for low-cost rapid antigen COVID-19 test with a good diagnostic performance. Although various antigen rapid detection tests are widely available, strong evidence of their usefulness in clinical practice are still limited. Therefore, our aim was to evaluate clinical performance of STANDARD Q COVID-19 Ag Test (SD Biosensor, Gyeonggi-do, South Korea). Methods The performance of the STANDARD Q COVID-19 Ag Test for the detection of SARS-CoV-2 antigen was evaluated in comparison to RT-qPCR results in 120 symptomatic patients (median age 49, IQR 36–70) who presented to health care facility in Novi Sad, Vojvodina, Serbia. Results Twenty five out of 120 samples have been tested positive using STANDARD Q COVID-19 Ag Test, and all of them were also positive on RT-qPCR. Overall, the STANDARD Q COVID-19 Ag Test showed sensitivity of 58.1% (95% CI 42.1–73.0) but it was higher in the early days of disease, when the highest viral loads were detected. During the first five days after the symptom onset, the sensitivity ranged from 66.7% to 100% and the pooled accuracy and Kappa values were high (0.92 and 0.852). Conclusions A strong agreement between performance of STANDARD Q COVID-19 Ag Test and RT-qPCR was observed during the first five days of illness, suggesting that this rapid antigenic test can be very useful for COVID-19 diagnosis in the early phase of disease.

scholarly journals Immunologic testing for SARS-CoV-2 infection from the antigen perspective

2020 ◽  
pp. JCM.02160-20
Author(s):  
Dandan Li ◽  
Jinming Li
Keyword(s):  
Cross Reactivity ◽  
Diagnostic Methods ◽  
Clinical Samples ◽  
Serological Testing ◽  
S Protein ◽  
N Protein ◽  
Viral Loads ◽  
Improved Performance ◽  
Human Coronaviruses ◽  
Novel Coronavirus

Coronavirus disease 2019 (COVID-19) caused by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally as a severe pandemic. SARS-CoV-2 infection stimulates antigen-specific antibody responses. Multiple serologic tests have been developed for SARS-CoV-2. However, which antigens are most suitable for serological testing remains poorly understood. Specifically, which antigens have the highest sensitivity and specificity for serological testing and which have the least cross-reactivity with other coronaviruses are currently unknown. Previous studies have shown that the S1 domain of the spike (S) protein has very low cross-reactivity between epidemic coronaviruses and common human coronaviruses, whereas the S2 domain of the S protein, and the nucleocapsid protein (N protein) show low-level cross-reactivity. Therefore, S1 is considered more specific than the native homotrimer of the S protein, and the receptor-binding domain as an antigen to test patient antibodies is more sensitive than the native N protein. In addition, an increasing number of studies have used multi-antigen protein arrays to screen serum from convalescent patients with COVID-19. Antigen combinations demonstrated improved performance as compared to each individual antigen. For rapid antigen detection, the sensitivity of the test is higher in the first week of onset of the disease with high viral loads. Highly sensitive and specific immunological diagnostic methods for antibodies or those that directly detect viral antigens in clinical samples would be beneficial for the rapid and accurate diagnosis of SARS-CoV-2 infection.

scholarly journals Saliva Is a Valid Alternative to Nasopharyngeal Swab in Chemiluminescence-Based Assay for Detection of SARS-CoV-2 Antigen

2021 ◽  
Vol 10 (7) ◽  
pp. 1471
Author(s):  
Alessandra Amendola ◽  
Giuseppe Sberna ◽  
Eleonora Lalle ◽  
Francesca Colavita ◽  
Concetta Castilletti ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Clinical Performance ◽  
Diagnostic Methods ◽  
Clinical Samples ◽  
Nasopharyngeal Swab ◽  
Promising Alternative ◽  
Viral Loads ◽  
Healthy Donors ◽  
Antigen Assay ◽  
Highly Correlated

Diagnostic methods based on SARS-CoV-2 antigens detection are a promising alternative to SARS-CoV-2 RNA amplification. We evaluated the automated chemiluminescence-based Lumipulse® G SARS-CoV-2 Ag assay on saliva samples, using Simplexa™ COVID-19 Direct assay as a reference test. Analytical performance was established on a pool of healthy donors’ saliva samples spiked with the 2019-nCoV/Italy-INMI1 isolate, whereas clinical performance was assessed on fresh saliva specimens collected from hospitalized patients with suspect or confirmed COVID-19 diagnosis. The limit of detection (LOD) was 0.65 Log TCID50/mL, corresponding to 18,197 copies/mL of SARS-CoV-2 RNA. Antigen concentrations and SARS-CoV-2 RNA were highly correlated (r = 0.99; p < 0.0001). Substantial agreement (80.3%) and significant correlation (r = −0.675; p = 0.0006) were observed between Lumipulse® G assay results and Ct values on clinical samples, with 52.4% sensitivity and specificity 94.1%. Sensitivity exceeded 90.0% when calculated on samples with Ct < 25, and specificity was 100% when excluding samples from recovered patients with previous COVID-19 diagnosis. Overall, chemiluminescence-based antigen assay may be reliably applied to saliva samples to identify individuals with high viral loads, more likely to transmit the virus. However, the low positive predictive value in a context of low SARS-CoV-2 prevalence underscores the need for confirmatory testing in SARS-CoV-2 antigen-positive cases.

scholarly journals The evaluation of a novel digital immunochromatographic assay with silver amplification to detect SARS-CoV-2

2021 ◽  
Author(s):  
Yoko Kurihara ◽  
Yoshihiko Kiyasu ◽  
Yusaku Akashi ◽  
Yuto Takeuchi ◽  
Kenji Narahara ◽  
...  
Keyword(s):  
Predictive Value ◽  
Limit Of Detection ◽  
The Other ◽  
Nucleic Acid Amplification ◽  
Immunochromatographic Assay ◽  
Clinical Samples ◽  
Antigen Test ◽  
Rt Pcr ◽  
Reverse Transcription Pcr ◽  
Antigen Tests

Introduction Rapid antigen tests are convenient for diagnosing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); however, they have lower sensitivities than nucleic acid amplification tests. In this study, we evaluated the diagnostic performance of Quick Chaser Auto SARS-CoV-2, a novel digital immunochromatographic assay that is expected to have higher sensitivity than conventional antigen tests. Methods A prospective observational study was conducted between February 8 and March 24, 2021. We simultaneously obtained two nasopharyngeal samples, one for evaluation with the QuickChaser Auto SARS-CoV-2 antigen test and the other for assessment with reverse transcription PCR (RT-PCR), considered the gold-standard reference test. The limit of detection (LOD) of the new antigen test was compared with those of four other commercially available rapid antigen tests. Results A total of 1401 samples were analyzed. SARS-CoV-2 was detected by reference RT-PCR in 83 (5.9%) samples, of which 36 (43.4%) were collected from symptomatic patients. The sensitivity, specificity, positive predictive value, and negative predictive value were 74.7% (95% confidence interval (CI): 64.0-83.6%), 99.8% (95% CI: 99.5-100%), 96.9% (95% CI: 89.2-99.6%), and 98.4% (95% CI: 97.6-99.0%), respectively. When limited to samples with a cycle threshold (Ct) <30 or those from symptomatic patients, the sensitivity increased to 98.3% and 88.9%, respectively. The QuickChaser Auto SARS-CoV-2 detected 34-120 copies/test, which indicated greater sensitivity than the other rapid antigen tests. Conclusions QuickChaser Auto SARS-CoV-2 showed sufficient sensitivity and specificity in clinical samples of symptomatic patients. The sensitivity was comparable to RT-PCR in samples with Ct<30.

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