scholarly journals Comparison of Antigen Tests and qPCR in Rapid Diagnostics of Infections Caused by SARS-CoV-2 Virus

Viruses ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 17
Author(s):  
Adrianna Klajmon ◽  
Aldona Olechowska-Jarząb ◽  
Dominika Salamon ◽  
Agnieszka Sroka-Oleksiak ◽  
Monika Brzychczy-Włoch ◽  
...  
Keyword(s):  
Quantitative Polymerase Chain Reaction ◽  
Molecular Techniques ◽  
Nucleic Acid Amplification ◽  
Laboratory Diagnostics ◽  
Test Results ◽  
Rapid Diagnostics ◽  
Antigen Test ◽  
Qualified Personnel ◽  
Replication Phase ◽  
Antigen Tests

Diagnostics of the coronavirus disease 2019 (COVID-19) using molecular techniques from the collected respiratory swab specimens requires well-equipped laboratory and qualified personnel, also it needs several hours of waiting for results and is expensive. Antigen tests appear to be faster and cheaper but their sensitivity and specificity are debatable. The aim of this study was to compare a selected antigen test with quantitative polymerase chain reaction (qPCR) tests results. Nasopharyngeal swabs were collected from 192 patients with COVID-19 symptoms. All samples were tested using Vitassay qPCR SARS-CoV-2 kit and the Humasis COVID-19 Ag Test (MedSun) antigen immunochromatographic test simultaneously. Ultimately, 189 samples were tested; 3 samples were excluded due to errors in taking swabs. The qPCR and antigen test results were as follows: 47 positive and 142 negative, and 45 positive and 144 negative, respectively. Calculated sensitivity of 91.5% and specificity of 98.6% for the antigen test shows differences which are not statistically significant in comparison to qPCR. Our study showed that effectiveness of the antigen tests in rapid laboratory diagnostics is high enough to be an alternative and support for nucleic acid amplification tests (NAAT) in the virus replication phase in the course of COVID-19.

scholarly journals Performance characteristics of the Abbott BinaxNOW SARS-CoV-2 antigen test in comparison to real-time RT-PCR and viral culture in community testing sites during November 2020

2021 ◽  
Author(s):  
Olivia Almendares ◽  
Jessica L. Prince-Guerra ◽  
Leisha D. Nolen ◽  
Jayleen K.L. Gunn ◽  
Ariella P. Dale ◽  
...  
Keyword(s):  
Real Time ◽  
Point Of Care ◽  
Exposure Period ◽  
Rapid Identification ◽  
Nucleic Acid Amplification ◽  
Test Results ◽  
Antigen Test ◽  
Viral Culture ◽  
Pima County ◽  
Antigen Tests

Point-of-care antigen tests are an important tool for SARS-CoV-2 detection. Antigen tests are less sensitive than real-time reverse-transcriptase PCR (rRT-PCR). Data on the performance of the BinaxNOW antigen test compared to rRT-PCR and viral culture by symptom and known exposure status, timing during disease or exposure period and demographic variables are limited. During November 3 rd -17 th , 2020, we collected paired upper respiratory swab specimens to test for SARS-CoV-2 by rRT-PCR and Abbott BinaxNOW (BinaxNOW) antigen test at two community testing sites in Pima County, Arizona. We administered a questionnaire to capture symptoms, known exposure status and previous SARS-CoV-2 test results. Specimens positive by either test were analyzed by viral culture. Previously we showed overall BinaxNOW sensitivity was 52.5%. Here we showed BinaxNOW sensitivity increased to 65.7% among currently symptomatic individuals reporting a known exposure. BinaxNOW sensitivity was lower among participants with a known exposure and previously symptomatic (32.4%) or never symptomatic (47.1%) within 14 days of testing. Sensitivity was 71.1% in participants within a week of symptom onset. In participants with a known exposure, sensitivity was highest 8-10 days post-exposure (75%). The positive predictive value for recovery of virus in cell culture was 56.7% for BinaxNOW-positive and 35.4% for rRT-PCR-positive specimens. Result reporting time was 2.5 hours for BinaxNOW and 26 hours for rRT-PCR. Point-of-care antigen tests have a shorter turn-around time compared to laboratory-based nucleic acid amplification tests, which allows for more rapid identification of infected individuals. Antigen test sensitivity limitations are important to consider when developing a testing program.

scholarly journals Combining Rapid Antigen Testing and Syndromic Surveillance Improves Community-Based COVID-19 Detection in Low-to-Middle-Income Countries

2022 ◽  
Author(s):  
Fergus Chadwick ◽  
Jessica Clark ◽  
Shayan Chowdhury ◽  
Tasnuva Chowdhury ◽  
David Pascall ◽  
...  
Keyword(s):  
Low Income ◽  
Syndromic Surveillance ◽  
Classification Performance ◽  
Test Results ◽  
Rapid Diagnostics ◽  
Antigen Test ◽  
Middle Income ◽  
Middle Income Countries ◽  
Antigen Tests ◽  
Antigen Testing

Abstract Diagnostics for COVID-19 detection are limited in many settings. Syndromic surveillance is often the only means to identify cases, but lacks specificity. Rapid antigen testing is inexpensive and easy-to-deploy but concerns remain about sensitivity. We examine how combining these approaches can improve surveillance for guiding interventions in low-income communities in Dhaka, Bangladesh. Rapid-antigen-tests and PCR validation was performed on 1172 symptomatically-identified individuals at home. Statistical models were fit to predict PCR status using rapid-antigen-test results, syndromic data, and their combination. Model predictive and classification performance was examined under contrasting epidemiological scenarios to evaluate their potential for improving diagnoses. Models combining rapid-antigen-test and syndromic data yielded equal-to-better performance to rapid-antigen-test-only models across all scenarios. These results show that drawing on complementary strengths across two rapid diagnostics, improves COVID-19 detection, and reduces false-positive and -negative diagnoses to match local requirements; improvements achievable without additional expense, or changes for patients or practitioners.

Correlation of COVID-19 antigen test and CBNAAT results at a single tertiary care hospital in North India: an experience

2021 ◽  
Vol 8 (5) ◽  
pp. 2427
Author(s):  
Surbhi Gupta ◽  
Anju Shukla ◽  
Poonam Singh ◽  
Areena H. Siddiqui
Keyword(s):  
Tertiary Care Hospital ◽  
Point Of Care ◽  
Tertiary Care ◽  
Uttar Pradesh ◽  
Nucleic Acid Amplification ◽  
North India ◽  
Care Hospital ◽  
Antigen Test ◽  
Discordant Group ◽  
Antigen Tests

Background: Nucleic acid amplification test (NAAT) is considered gold standard in the molecular diagnosis of CoV-2 infection but since it is costly, labor intensive and needs technical expertise, rapid chromatographic immunoassay for the qualitative detection of specific antigens to SARS CoV-2 have been devised. Objectives of this study was to compare the results of Antigen test and NAAT for CoV-2 infection carried out during the months of July and August 2020 by single tertiary care hospital in Lucknow, Uttar Pradesh and to determine the utility of rapid antigen test in the SARS CoV-2 diagnosis.Methods: All the patients who came to our hospital seeking admission during July 2020 and August 2020 were included in the study. A total of 1000 patients were included in this study.Results: Out of a total 1000 cases which were included in the study, 769 cases (76.9%) were found to be SARS CoV-2 negative by both antigen and CBNAAT, 100 cases (10.0%) were SARS CoV-2 positive by both antigen and CBNAAT tests. But in 131 cases (13.1%), antigen was not able to pick up the disease. It was also found that the Cycle Threshold (Ct) value for the discordant group was higher (Mean E= 28, Mean N2=33) when compared to the group where antigen was positive.Conclusions: The present study establishes the role of rapid antigen tests in contributing to the quick, point of care diagnosis of SARS CoV-2. These assays are safe, simple, and fast and can be used in local clinics and hospitals. These tests are very important for real-time patient management and infection control decision.

scholarly journals Diagnostic performance of a novel digital immunoassay (RapidTesta SARS-CoV-2): a prospective observational study with 1,127 nasopharyngeal samples

2021 ◽  
Author(s):  
Hiromichi Suzuki ◽  
Yusaku Akashi ◽  
Atsuo Ueda ◽  
Yoshihiko Kiyasu ◽  
Yuto Takeuchi ◽  
...  
Keyword(s):  
Diagnostic Performance ◽  
Prospective Observational Study ◽  
Test Results ◽  
Antigen Test ◽  
Rt Pcr ◽  
Asymptomatic Patients ◽  
Pcr Method ◽  
Antigen Tests ◽  
Positive Line ◽  
Test Cassette

Introduction: Digital immunoassays are generally regarded as superior tests for the detection of infectious disease pathogens, but there have been insufficient data concerning SARS-CoV-2 immunoassays. Methods: We prospectively evaluated a novel digital immunoassay (RapidTesta SARS-CoV-2). Two nasopharyngeal samples were simultaneously collected for antigen tests and RT-PCR. Real-time RT-PCR for SARS-CoV-2, using a method developed by the National Institute of Infectious Diseases, Japan, served as the reference RT-PCR method. Results: During the study period, 1,127 nasopharyngeal samples (symptomatic patients: 802, asymptomatic patients: 325) were evaluated. For digital immunoassay antigen tests, the sensitivity was 78.3% (95% CI: 67.3%-87.1%) and the specificity was 97.6% (95% CI: 96.5%-98.5%). When technicians visually analyzed the antigen test results, the sensitivity was 71.6% (95% CI: 59.9%-81.5%) and the specificity was 99.2% (95% CI: 98.5%-99.7%). Among symptomatic patients, the sensitivity was 89.4% (95% CI; 76.9%-96.5%) with digital immunoassay antigen tests, and 85.1% (95% CI; 71.7%-93.8%) with visually analyzed the antigen test, respectively. Conclusions: The findings indicated that RapidTesta SARS-CoV-2 analysis with the DIA device had sufficient analytical performance for the detection of SARS-CoV-2 in nasopharyngeal samples. When positive DIA results are recorded without a visually recognizable red line at the positive line location on the test cassette, additional RT-PCR evaluation should be performed.

Diagnosing Emerging and Reemerging Infectious Diseases: The Pivotal Role of the Pathologist

2011 ◽  
Vol 135 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Juan P. Olano ◽  
David H. Walker
Keyword(s):  
Nucleic Acid ◽  
Infectious Diseases ◽  
Molecular Diagnostics ◽  
Clinical Setting ◽  
Driving Forces ◽  
Molecular Techniques ◽  
Nucleic Acid Amplification ◽  
Pivotal Role ◽  
Laboratory Diagnostics ◽  
Molecular Tools

Abstract Context—Molecular diagnostics continues to evolve very rapidly, and its impact in the diagnosis of infectious diseases is undeniable. Molecular tools have played a pivotal role in discovering and characterizing several emerging infectious agents and have now become the gold standard for the diagnosis of infectious diseases caused by fastidious or uncultivable agents. Multiple challenges still remain for the widespread use of cost-effective, validated, and commercially available molecular tools. Automated instruments capable of sample processing and multiplex nucleic acid amplification and postamplification analysis have already been approved by the US Food and Drug Administration (FDA) for use in the clinical setting. Nanobiotechnology is beginning to impact laboratory diagnostics in the clinical setting. Objective—To address current nucleic acid techniques used in the clinical laboratory for diagnosis of infectious diseases. FDA-approved tests are listed, as well as molecular techniques (amplification and postamplification analysis). A comprehensive list of emerging pathogens during the last 4 decades is also presented. Biosurveillance systems are discussed in the context of molecular tools. The rapidly evolving field of nanobiotechnology is briefly addressed. Data Sources—Original publications, major reviews, and book chapters were used to present a comprehensive, yet short, review of molecular diagnostics in infectious diseases. Conclusions—We will continue to witness an exponential growth of molecular techniques used for the initial diagnosis of infectious diseases. Molecular tools will also continue to have an impact on disease prognosis and response to therapeutic interventions. Automation, multiplexing, and miniaturization will continue to be driving forces in the development of new instruments.

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.

scholarly journals Application of a Serial Antigen Based Testing Strategy for SARS-CoV-2 and Student Adherence in a University Setting, Wisconsin — October–November 2020

2021 ◽  
Author(s):  
John Paul Bigouette ◽  
Laura Ford ◽  
Ian Pray ◽  
Kimberly Langolf ◽  
Juliana Kahrs ◽  
...  
Keyword(s):  
Male Students ◽  
Test Results ◽  
Antigen Test ◽  
Testing Strategy ◽  
Rt Pcr ◽  
Testing Strategies ◽  
Serial Testing ◽  
Polymerase Chain ◽  
Antigen Tests ◽  
University Setting

Abstract Background Serial SARS-CoV-2 testing has been implemented at institutions of higher education (IHEs) and other settings. Testing strategies can include algorithms specifying confirmatory reverse transcription polymerase chain reaction (RT-PCR) testing after an antigen test. It is unknown how testing strategies perform detecting SARS-CoV-2, including individual adherence to serial testing requirements. Methods Student serial testing adherence was defined as completing ≥80% of weekly tests from October 5–November 14, 2020 and evaluated using logistic regression. Medical records were reviewed for all positive antigen test encounters and 10% of daily negative antigen test encounters during October 19–November 30, 2020. Results were used to estimate the proportion of individuals requiring only antigen tests, requiring and completing RT-PCR testing, and associated costs of tests. Results Two-thirds (66.5%; 1,166/1,754) of eligible on-campus students adhered to weekly testing; female students were more adherent (adjusted odds ratio [aOR]:2.07, 95% CI:1.66–2.59) than male students. Of all antigen test encounters, 11.5% (1,409/12,305) reported &gt;1 COVID-19 symptoms. Of non-COVID-19 exposed antigen test encounters, 88% (10,386/11,769) did not require confirmatory RT-PCR testing. Only 28% (390/1,387) of testing encounters had an associated recommended confirmatory RT-PCR test performed. We estimated the testing strategy captured 61% (235/389) of predicted RT-PCR positive specimens. Conclusions At this IHE, most students voluntarily adhered to serial testing. The majority of antigen test results did not require confirmatory RT-PCR testing, but when required, most students did not obtain it. Including strategies to increase the proportion of individuals obtaining indicated confirmatory testing might improve the testing program’s performance.

scholarly journals 674. Evaluation of the Access Bio CareStart™ Rapid SARS-CoV-2 Antigen Test in Asymptomatic Individuals Tested at a Community Mass-testing Program in Western Massachusetts

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S439-S439
Author(s):  
Wilfredo Matias ◽  
Sara suliman ◽  
Isabel Fulcher ◽  
Francisco Molano ◽  
Shannon Collins ◽  
...  
Keyword(s):  
Point Of Care ◽  
Quantitative Polymerase Chain Reaction ◽  
Rapid Test ◽  
High Specificity ◽  
Population Data ◽  
Performance Characteristics ◽  
Test Results ◽  
Antigen Test ◽  
Predictive Values ◽  
Cycle Threshold

Abstract Background Point-of-care antigen-detecting rapid diagnostic tests (RDTs) to detect Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) represent a scalable tool for surveillance of active SARS-CoV-2 infections in the population. Data on the performance of these tests in real-world community settings will be paramount for their implementation to combat the COVID-19 pandemic. Methods We evaluated the performance characteristics of the CareStartTM COVID-19 Antigen Test (CareStart) in a community testing site in Holyoke, Massachusetts. We compared CareStart to a SARS-CoV-2 reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) reference, both using anterior nasal swab samples. We calculated the sensitivity, specificity, and the expected positive and negative predictive values at different SARS-CoV-2 prevalence estimates. Results We performed 666 total tests on 591 unique individuals. 573 (86%) were asymptomatic. There were 52 positive tests by RT-qPCR. The sensitivity of CareStart was 49.0% (95% Confidence Interval (CI): 34.8 – 63.4) and specificity was 99.5% (95% CI: 98.5 – 99.9). Among positive RT-qPCR tests, the median cycle threshold (Ct) was significantly lower in samples that tested positive on CareStart. Using a Ct less than or equal to 30 as a benchmark for positivity increased the sensitivity of the test to 64.9% (95% CI: 47.5 – 79.8). Performance characteristics of CareStart test results benchmarked against the RT-qPCR gold standard (excluding undetermined results). Examples of images of CareStart rapid test showing variable band intensities. N2 gene RT-qPCR Cycle threshold (Ct) values corresponding to positive and negative CareStart rapid antigen test results for all RT-qPCR positive samples (n=52). Conclusion Our study shows that CareStart has a high specificity and moderate sensitivity. The utility of RDTs, such as CareStart, in mass implementation should prioritize use cases in which a higher specificity is more important, such as triage tests to rule-in active infections in community surveillance programs. Disclosures All Authors: No reported disclosures

scholarly journals Performance of antigenic detection of SARS-CoV-2 in nasopharyngeal samples

2021 ◽  
Author(s):  
Catalina Lunca ◽  
Cristian Cojocaru ◽  
Irina Luciana Gurzu ◽  
Florin Dumitru Petrariu ◽  
Elena Cojocaru
Keyword(s):  
Virus Detection ◽  
Protein Detection ◽  
Protein S ◽  
Screening Tests ◽  
Test Results ◽  
Antigen Test ◽  
Qrt Pcr ◽  
Qualitative Detection ◽  
Antigen Tests ◽  
Pcr Test

Objectives: SARS-CoV-2 virus detection on nasopharyngeal specimens to infected individuals has become a challenge for the COVID-19 pandemic outbreak. We aim at comparing the performance of antigenic detection of SARS-CoV-2 in nasopharyngeal samples via an immunochromatographic method to molecular detection via qRT-PCR. Materials and Methods: 47 nasopharyngeal exudates were collected from suspicious COVID-19 cases. The samples were performed both via the qualitative immuno-chromatographic method for S protein detection in the SARS-CoV-2 structure, using fluorescent labelled anti-protein S antibodies and via qRT-PCR test for the qualitative detection of the screening gene E and the specific ORF1ab region of the RNA-SARS-CoV-2. Results: There was a fair correlation between the positive antigen tests and the positive PCR assays measured through threshold cycle ORF1ab region (Ct orf). A better correlation was obtained between the antigen test results and the Ct orf when including patients with Ct orf below 25. Conclusions: Using antigen tests as screening tests is useful on symptomatic persons during the viral replication period, therefore during the contagious period. A positive test shows a high predictive value for infection, while a negative antigen test result via immuno-chromatography must be confirmed by a qRT-PCR test.

scholarly journals Assessment of twenty-two SARS-CoV-2 rapid antigen tests against SARS-CoV-2: A laboratory evaluation study

2021 ◽  
Author(s):  
Joshua M Deerain ◽  
Thomas Tran ◽  
Mitchell B Batty ◽  
Yano Yoga ◽  
Julian Druce ◽  
...  
Keyword(s):  
Cell Culture ◽  
Population Level ◽  
Evaluation Study ◽  
Transmission Risk ◽  
Laboratory Evaluation ◽  
Analytical Sensitivity ◽  
Test Results ◽  
Antigen Test ◽  
Clinical Sensitivity ◽  
Antigen Tests

Background Rapid antigen testing is widely used as a way of scaling up population-level testing. To better inform antigen test deployment in Australia, we evaluated 22 commercially available antigen tests, including an assessment of culture infectivity. Methods Analytical sensitivity was evaluated against SARS-CoV-2 B.1.617.2 (Delta), reported as TCID50/mL, cycle threshold (Ct) value and viral load (RNA copies/mL). Specificity was assessed against non-SARS-CoV-2 viruses. Clinical sensitivity and correlation with cell culture infectivity was assessed using the Abbott PanBio™ COVID-19 Ag test. Results Nineteen kits consistently detected SARS-CoV-2 antigen equivalent to 1.3x10^6 copies/mL (5.8x10^3 TCID50/mL). Specificity for all kits was 100%. Compared to RT-PCR the Abbott PanBio™ COVID-19 Ag test was 52.6% (95% CI, 41.6% to 63.3%) sensitive, with a 50% detection probability for infectious cell culture at 5.9 log10 RNA copies/mL (95% CI, 5.3 to 6.5 log10 copies/mL). Antigen test sensitivity was 97.6% (95% CI, 86.3% to 100.0%) compared to positive infectious in cell culture. Conclusions Antigen test positivity correlated with positive viral culture, suggesting antigen test results may determine SARS-CoV-2 transmission risk. Sensitivity varied considerably between test kits and highlights the need for ongoing systematic post-market evaluation, providing valuable information to help guide antigen test selection and deployment.

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