scholarly journals Clinical evaluation of the SD Biosensor SARS-CoV-2 saliva antigen rapid test with symptomatic and asymptomatic, non-hospitalized patients

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260894
Author(s):  
Zsofia Igloi ◽  
Jans Velzing ◽  
Robin Huisman ◽  
Corine Geurtsvankessel ◽  
Anoushka Comvalius ◽  
...  
Keyword(s):  
Saliva Sample ◽  
Rapid Test ◽  
Hospitalized Patients ◽  
Nasopharyngeal Swab ◽  
Lower Sensitivity ◽  
Rt Pcr ◽  
Virus Culture ◽  
Testing Site ◽  
Asymptomatic Individuals ◽  
Post Onset

Background Performance of the SD Biosensor saliva antigen rapid test was evaluated at a large designated testing site in non-hospitalized patients, with or without symptoms. Method All eligible people over 18 years of age presenting for a booked appointment at the designated SARS-CoV-2 testing site were approached for inclusion and enrolled following verbal informed consent. One nasopharyngeal swab was taken to carry out the default antigen rapid test from which the results were reported back to the patient and one saliva sample was self-taken according to verbal instruction on site. This was used for the saliva antigen rapid test, the RT-PCR and for virus culture. Sensitivity of the saliva antigen rapid test was analyzed in two ways: i, compared to saliva RT-PCR; and ii, compared to virus culture of the saliva samples. Study participants were also asked to fill in a short questionnaire stating age, sex, date of symptom onset. Recommended time of ≥30mins since last meal, drink or cigarette if applicable was also recorded. The study was carried out in February-March 2021 for 4 weeks. Results We could include 789 people with complete records and results. Compared to saliva RT-PCR, overall sensitivity and specificity of the saliva antigen rapid test was 66.1% and 99.6% which increased to 88.6% with Ct ≤30 cutoff. Analysis by days post onset did not result in higher sensitivities because the large majority of people were in the very early phase of disease ie <3 days post onset. When breaking down the data for symptomatic and asymptomatic individuals, sensitivity ranged from 69.2% to 50% respectively, however the total number of RT-PCR positive asymptomatic participants was very low (n = 5). Importantly, almost all culture positive samples were detected by the rapid test. Conclusion Overall, the potential benefits of saliva antigen rapid test, could outweigh the lower sensitivity compared to nasopharyngeal antigen rapid test in a comprehensive testing strategy, especially for home/self-testing and in vulnerable populations like elderly, disabled or children where in intrusive testing is either not possible or causes unnecessary stress.

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 Clinical evaluation of the SD Biosensor saliva antigen rapid test with symptomatic and asymptomatic, non-hospitalized patients

2021 ◽  
Author(s):  
Zsofia Igloi ◽  
Jans Velzing ◽  
Robin Huisman ◽  
Corine Geurtsvankessel ◽  
Anoushka Comvalius ◽  
...  
Keyword(s):  
Clinical Evaluation ◽  
Rapid Test ◽  
Hospitalized Patients ◽  
Rt Pcr ◽  
Cycle Threshold ◽  
Virus Culture

AbstractPerformance of saliva antigen rapid test was evaluated in non-hospitalized patients, with or without symptoms. Overall sensitivity was 66.1% compared to RT-PCR in saliva. Using cycle threshold <30 cutoff or virus culture as reference, sensitivity increased to 88.6% or 96.7% respectively. Specificity was 99.6%.

scholarly journals SARS-CoV-2 in peritoneal swabs from asymptomatic patients undergoing emergency abdominal surgery

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Jasim AlAradi ◽  
Rawan A Rahman AlHarmi ◽  
Mariam AlKooheji ◽  
Sayed Ali Almahari ◽  
Mohamed Abdulla Isa ◽  
...  
Keyword(s):  
Peritoneal Fluid ◽  
Case Series ◽  
Rapid Test ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Protective Measures ◽  
The Public ◽  
Asymptomatic Patients ◽  
Number Of Patients ◽  
Viral Transfer

Abstract This is a case series of five patients with acute abdomen requiring surgery who tested positive for coronavirus disease 2019 (COVID-19) and were asymptomatic, with the purpose of detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in peritoneal fluid. Nasopharyngeal swab was done as a prerequisite for admission or prior to admission as part of random testing. Two methods of viral testing were employed: Xpert® Xpress SARS-CoV-2 (rapid test) and real-time reverse transcription polymerase chain reaction (RT-PCR). Either or both tests were done, with the former performed for patients requiring surgery immediately. Surgery was performed within 24–36 h from admission. Peritoneal fluid swabs were obtained for the detection of SARS-CoV-2 using RT-PCR test. Swabs were immediately placed in viral transfer media and delivered to the public health laboratory in an ice bag. SARS-CoV-2 was not detected in peritoneal swabs. Due to the limited number of patients, further studies are required; yet, protective measures should still be taken by surgeons when dealing with COVID-19 cases.

scholarly journals Validation of rapid antibody (IgG-IgM) test kit for SARS COV-2 infection in Qatar

2021 ◽  
Author(s):  
Jesha Mundodan ◽  
Samina Hasnain ◽  
Hayat Khogali ◽  
Soha Shawqi Al Bayat ◽  
Dina Ali ◽  
...  
Keyword(s):  
Predictive Value ◽  
Local Population ◽  
Rapid Test ◽  
Antibody Test ◽  
Molecular Testing ◽  
Rt Pcr ◽  
Test Kit ◽  
Asymptomatic Individuals ◽  
Sensitivity Specificity ◽  
Rapid Antibody

Background: In response to the growing coronavirus disease 2019 (COVID-19) pandemic and the shortage of laboratory based molecular testing capacity and reagents, multiple diagnostic test manufacturers have developed rapid and easy to use devices to facilitate testing outside laboratory settings. These kits are either based on detection of proteins from SARS-CoV-2 virus or detection of antigen or human antibodies generated in response to the infection. However, it is important to understand their performance characteristics and they must be validated in the local population setting.Design and Methods: The objective is to assess the validity of the rapid test for IgG and IgM immunoglobulins compared to the current gold standard reverse transcription polymerase chain reaction (RT-PCR) test. A total of 16951 asymptomatic individuals were tested by the Ministry of Public Health track-and-trace team using both rapid immunodiagnostic test and RT-PCR as part of screening across various random settings with potential risk of community interaction prior to gradual lifting of restrictions in Qatar.  Rapid test was considered to be posiive if both IgG and IgM are positive, while only IgG/IgM positive was considered as rapid test negative. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated.Results: The sensitivity of rapid test kit was found to be 0.9%, whereas the specificity was found to be 97.8%. the PPV was found to be 0.3% whereas the NPV was found to be 99.4%.Conclusion: Based on the outcome and results of the study, it appears that the sensitivity and PPV of the rapid antibody test are low. As such, this test is not recommended for use to assist in taking clinic-based decisions or decisions related to quarantine/isolation.

scholarly journals Direct Quantitation of SARS-CoV-2 Using Droplet Digital PCR in Suspected Samples With Very Low Viral Load

2021 ◽  
Author(s):  
Michela Deiana ◽  
Chiara Piubelli ◽  
Antonio Mori ◽  
Gian Paolo Chiecchi ◽  
Giulia La Marca ◽  
...  
Keyword(s):  
Viral Load ◽  
Real Time ◽  
False Negative ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Hospitalized Patients ◽  
Lower Sensitivity ◽  
Rt Pcr ◽  
Viral Genes ◽  
Viral Target

Background: The reference test for SARS-CoV-2 detection is the reverse transcriptase real time PCR (real time RT-PCR). However, evidences reported that real time RT-PCR has a lower sensitivity compared with the droplet digital PCR (ddPCR) leading to possible false negative in low viral load cases. Methods: We used ddPCR for viral genes N1 and N2 on 20 negative (no detection) samples from symptomatic hospitalized COVID-patients presenting fluctuating real time RT-PCR results and 10 suspected samples (Ct value&gt;35) from asymptomatic not hospitalized subjects. Results: ddPCR performed on RNA revealed 65% of positivity for at least one viral target in the hospitalized patients group of samples (35% for N1 and N2, 10% only for N1 and 20% only for N2) and 50% in the suspected cases (30% for N1 and N2, while 20% only for N2). On hospitalized patients&rsquo; samples, we applied also a direct ddPCR approach on the swab material, achieving an overall positivity of 83%. Conclusion: ddPCR, in particular the direct quantitation on swabs, shows a sensitivity advantage for the SARS-CoV-2 identification and may be useful to reduce the false negative diagnosis, especially for low viral load suspected samples.

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 comparison of saliva and nasopharyngeal swab sampling for mass screening for COVID-19

2020 ◽  
Author(s):  
◽  
mathieu nacher ◽  
magalie demar
Keyword(s):  
Mass Screening ◽  
Saliva Sample ◽  
Field Testing ◽  
Contact Tracing ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Prospective Comparison ◽  
Asymptomatic Patients ◽  
Patient Groups ◽  
Trained Staff

Current testing for COVID-19 relies on quantitative reverse-transcriptase polymerase chain reaction from a nasopharyngeal swab specimen. Saliva samples have advantages regarding ease and painlessness of collection, which does not require trained staff and may allow self-sampling. We enrolled 776 persons at various field-testing sites and collected nasopharyngeal and pooled saliva samples. 162 had a positive COVID-19 RT-PCR, 61% were mildly symptomatic and 39% asymptomatic. The sensitivity of RT-PCR on saliva samples versus nasopharygeal swabs varied depending on the patient groups considered or on Ct thresholds. There were 10 (6.2%) patients with a positive saliva sample and a negative nasopharyngeal swab, all of whom had Ct values<25. For symptomatic patients for whom the interval between symptoms onset and sampling was <10 days sensitivity was 77% but when excluding persons with isolated Ngen positivity (54/162), sensitivity was 90%. In asymptomatic patients, the sensitivity was only 24%. When we looked at patients with Cts <30, sensitivity was 83% or 88.9% when considering 2 genes. The relatively good performance for patients with low Cts suggests that Saliva testing could be a useful and acceptable tool to identify infectious persons in mass screening contexts, a strategically important task for contact tracing and isolation in the community.

scholarly journals Diagnostic accuracy of two commercial SARS-CoV-2 antigen-detecting rapid tests at the point of care in community-based testing centers

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248921
Author(s):  
Alice Berger ◽  
Marie Therese Ngo Nsoga ◽  
Francisco Javier Perez-Rodriguez ◽  
Yasmine Abi Aad ◽  
Pascale Sattonnet-Roche ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Point Of Care ◽  
Rapid Test ◽  
Diagnostic Value ◽  
Ease Of Use ◽  
Lower Sensitivity ◽  
Rt Pcr ◽  
Test Device ◽  
Community Based ◽  
Rapid Tests

Objectives Determine the diagnostic accuracy of two antigen-detecting rapid diagnostic tests (Ag-RDT) for SARS-CoV-2 at the point of care and define individuals’ characteristics providing best performance. Methods We performed a prospective, single-center, point of care validation of two Ag-RDT in comparison to RT-PCR on nasopharyngeal swabs. Results Between October 9th and 23rd, 2020, 1064 participants were enrolled. The PanbioTM Covid-19 Ag Rapid Test device (Abbott) was validated in 535 participants, with 106 positive Ag-RDT results out of 124 positive RT-PCR individuals, yielding a sensitivity of 85.5% (95% CI: 78.0–91.2). Specificity was 100.0% (95% CI: 99.1–100) in 411 RT-PCR negative individuals. The Standard Q Ag-RDT (SD Biosensor, Roche) was validated in 529 participants, with 170 positive Ag-RDT results out of 191 positive RT-PCR individuals, yielding a sensitivity of 89.0% (95%CI: 83.7–93.1). One false positive result was obtained in 338 RT-PCR negative individuals, yielding a specificity of 99.7% (95%CI: 98.4–100). For individuals presenting with fever 1–5 days post symptom onset, combined Ag-RDT sensitivity was above 95%. Lower sensitivity of 88.2% was seen on the same day of symptom development (day 0). Conclusions We provide an independent validation of two widely available commercial Ag-RDTs, both meeting WHO criteria of ≥80% sensitivity and ≥97% specificity. Although less sensitive than RT-PCR, these assays could be beneficial due to their rapid results, ease of use, and independence from existing laboratory structures. Testing criteria focusing on patients with typical symptoms in their early symptomatic period onset could further increase diagnostic value.

scholarly journals Sensitivity of Nasopharyngeal Swabs and Saliva for the Detection of Severe Acute Respiratory Syndrome Coronavirus 2

2020 ◽  
Author(s):  
Alainna J Jamal ◽  
Mohammad Mozafarihashjin ◽  
Eric Coomes ◽  
Jeff Powis ◽  
Angel X Li ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Real Time ◽  
Saliva Sample ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Sample Pair

Abstract We enrolled 91 consecutive inpatients with COVID-19 at 6 hospitals in Toronto, Canada, and tested 1 nasopharyngeal swab/saliva sample pair from each patient using real-time RT-PCR for severe acute respiratory syndrome coronavirus 2. Sensitivity was 89% for nasopharyngeal swabs and 72% for saliva (P = .02). Difference in sensitivity was greatest for sample pairs collected later in illness.

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.

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